New Zealand Yearbook of International Law
Last Updated: 8 July 2015
BEREFT OF LIFE?
THE CHARTER PROHIBITION ON THE USE OF FORCE, NON-STATE ACTORS AND THE PLACE OF THE INTERNATIONAL COURT OF JUSTICE
The War on Terror has seen some states come to rely on a right of self-
defence to strike against non-state groups based in the territories
states. The International Court of Justice has determined that the self-defence
right cannot be utilised in such circumstances
but scholars have argued that
this position is overly restrictive and out of touch with contemporary state
practice. Moreover, these
scholars claim that a right of self-defence against
non-state groups is a reasonable and principled interpretation of the law. This
author argues that this expanded right to self-defence does not exist and should
not be brought into being. While a small group of
states have seen fit to engage
in unilateral and unlawful military actions in the territories of other states,
these actions reflect
an unfortunate departure from imperfect but fundamentally
sound jus ad bellum standards, in favour of ill-defined notions of
reasonable state conduct. The International Court of Justice must mount a
and more forthright defence of its restrictive interpretation of
the right to self-defence if the international rule of law is to
When Osama bin Laden was killed by United States forces in Pakistan in May 2011, media paid scant attention to the jus ad bellum issues associated with conducting a killing on foreign soil. Perhaps reflecting this lack of interest, the Obama Administration took a somewhat relaxed attitude to proffering a legal justification. When such a justification came, it took the extraordinary form of a blog post by the Department of State’s Legal Adviser, Harold Koh.1 The post included a reproduction of a speech Koh gave in 2010,2 in which he spoke generally about the legality of targeted killings, supplemented by new remarks relating to bin Laden specifically. Incredibly, despite being apparently the only official published legal justification for killing bin Laden, the implications of using military force on the territory of another state, a state with which the United States was not at war, were not discussed. Quoting from his earlier speech, Koh noted state sovereignty as a “consideration” in targeted killing operations along with “the willingness and ability of those states to suppress the threat the target poses.”3 Undoubtedly, the United States relies on self-defence to justify its continuing incursions into Pakistan; in one of the only other Administration statements on the legality of the bin Laden operation, Attorney-General Eric Holder was quoted as referring to it as “an act of national self-defence.”4 However, despite frequent reliance on the principle by the United States and others, the purpose, means and limits of self-defence against non-state actors are uncertain.
While jus in bello issues relating to detention, rendition, targeted killing and torture have taken centre stage as the War on Terror has rumbled on, the jus ad bellum legality of military action against non-state groups, within the territory of another state, has received less analysis. However, the International Court of Justice (ICJ) has expressed the view that the self-defence right, contained in art 51 of the United Nations Charter, cannot be expanded to include responses against non-state groups operating on the territory of other states.5 This view has been criticised as unduly restrictive by scholars who favour an expanded notion of self-defence, allowing responses against non-state groups. This article argues that those scholars are wrong and that the ICJ is right.
This article presents a robust defence of the orthodox restrictive interpretation. To provide context for this argument, Part II analyses the self-defence jurisprudence of the ICJ, with an emphasis on the role of non-state actors. Part III confronts and disproves the common pro-expansion argument that state practice and opinio juris, from Pakistan to Pankisi Gorge, shows an evolution of custom in favour of the expanded right. In Part IV, three additional mechanisms by which the expanded right could be brought into being are evaluated and, subject to a limited reform of the attribution threshold, dismissed. In Part V, the principled arguments supporting a restrictive interpretation of art 51 are canvassed. Finally, the article considers the way in which some states have seemingly abandoned the law in favour of notions of what is reasonable or just. A return to using the language of law, and a more prominent role for the ICJ, is advocated.
The expanded self-defence right is only the latest challenge to the
fundamental prohibition on the use of force contained in
art 2(4) of the
Charter. When Franck asked “Who Killed Article 2(4)?” in 1970, he
identified the wide disparity between
the norm art 2(4) sought to establish and
the practical goals of states, a disparity driven by the rise of wars of
the threat posed by nuclear weapons and the
authoritarianism of superpower-dominated regional systems.6 The tension between
rule of law and states’ interests continues but the distinctly Cold
War preoccupations of the past have been replaced by the
spectre of terrorist
groups harboured within states which are unwilling or unable to defeat them. The
mere fact that legal debate
continues about the scope of the self-defence
exception, as well as states’ efforts to categorise almost any
action within the self-defence rubric, suggests that art 2(4) is not
yet the “dead parrot” of international law. However,
as the War on
Terror continues, the prohibition on the use of force is at least in danger of
becoming bereft of life. While the ICJ
cannot prevent states from violating
international law, a principled, coherent defence of a restrictive right to
state attribution, would provide a clear standard
against which to evaluate future military actions based on self-defence.
II. The International Court of Justice’s Self-Defence
Self-defence concerns the interaction between art 2(4) and art 51 of the
United Nations Charter. Article 2(4) provides that Members
shall refrain from
the threat or use of force against the territorial or political independence of
any state. It follows on naturally
from art 2(3), which provides that
members shall settle their disputes through “peaceful means”. The
four exceptions against this fundamental prohibition. The first
and second are contained in Chapter VII and permit the Security Council
authorise uses of force directly (art 42) and through the utilisation of
regional arrangements under its authority (art 53). In
addition, the now
obsolete art 107 saves from illegality certain actions taken against
“enemy” powers in World War II.
The fourth and most important
exception for the purposes of this paper is contained in art 51, which
Nothing in the present Charter shall impair the inherent right of individual
or collective self-defence if an armed attack occurs
against a Member of the
United Nations, until the Security Council has taken measures necessary to
maintain international peace and
security. Measures taken by Members in the
exercise of this right of self-defence shall be immediately reported to the
and shall not in any way affect the authority and
responsibility of the Security Council under the present Charter to take at any
time such action as it deems necessary in order to maintain or restore
international peace and security.
Article 51’s status as the only exception to art 2(4) that permits a
state to act unilaterally makes its interpretation one
of the most contested
areas in the jus ad bellum. As international law’s supreme judicial
body, the International Court of Justice’s pronouncements on the topic are
great legal significance. However, as this article will demonstrate, some
powerful states have not seen fit to respect the Court’s
Accordingly, Part II seeks to rationalise the Court’s self-defence
jurisprudence into a coherent framework, providing
a lens through which the
primary focus of this article, the place of non-state actors, can be
B. Armed Attack
The requirement that an “armed attack” occur is contained in the
first sentence of art 51. The first piece of judicial
guidance on this phrase
appears in Military and Paramilitary Activities in and against Nicaragua
(Nicaragua v United States of America) where the Court stated that
“[i]n the case of individual self-defence, the exercise of this
[self-defence] right is subject
to the state concerned having been the victim of
an armed attack.”7 Subsequently in Oil Platforms (Islamic Republic of
Iran v United States of America) the Court made clear that “in order
to establish that it was legally justified in attacking the Iranian platforms
of the right of individual self-defence, the United States has to
show that attacks had been made upon it...were of such a nature
as to be
qualified as ‘armed attacks’ ...”8 An armed attack is
therefore the sine qua non of self-defence and much turns on its
definition. This core concept breaks down into two considerations: gravity and
of the perpetrator.
1. The Gravity Threshold
Nicaragua is the source of the gravity requirement, through which the Court sought to “distinguish the most grave forms of the use of force from other less grave forms”.9 Basing its discussion on the General Assembly’s 1974 Definition of Aggression, the Court provided some guidance as to which acts would constitute armed attacks. These include “action by regular armed forces across an international border” as well as the sending of “armed bands” by or on behalf of a state, to carry out acts of armed force against another state of such gravity as to amount to an armed attack by regular forces, or “substantial involvement therein.”10 The Court emphasised that attacks by armed bands would only amount to armed attacks “if such an operation, because of its scale and effects, would have been classified as an armed attack rather than as a mere frontier incident had it been carried out by regular armed forces.”11 Some academics have interpreted this to mean that while an attack by regular state forces will always be an “armed attack”, non-state forces, even though sent by a state, must meet the gravity threshold.12 For such a crucial point, the ambiguity of the Nicaragua statement is unfortunate. However, when the ICJ revisited the issue in Oil Platforms the Court indicated that attacks by states must also meet the gravity threshold, holding that the attacks of which the United States complained did not qualify as “most grave” forms of the use of force.13 This position attracted strong criticism as a departure from Nicaragua.14
As to what sort of actions would meet the gravity threshold, the Court in
Oil Platforms held that an attack on the US-flagged merchant vessel
Sea Isle City did not amount to an armed attack.15 However, the Court
also held that a mine attack on the USS Samuel B Roberts could
potentially amount to an armed attack but “in view of all the
circumstances, including the inconclusiveness of the evidence
responsibility for the mining of the USS Samuel B Roberts,” the
Court was unable to hold that it did amount to such.16 The vague reference to
“all the circumstances” obscures
the Court’s reasoning. If the
factor presenting a finding of armed attack in this case was simply that
for the mining had not been demonstrated, the Court
could have said so. Instead, the reader is left to speculate as to whether the
gravity threshold was met.17 Little assistance can be gleaned from the next
case relating to self-defence, Armed Activities on the Territory of the Congo
(Democratic Republic of Congo v Uganda), where the Court unfortunately did
not consider the issue, focussing instead on whether Uganda could attribute
rebel attacks to the
DRC.18 Of particular relevance to this paper is the
question of whether a series of small attacks, viewed together, can amount to
armed attack. This “doctrine of accumulation of events” is likely to
have application in the case of non-state actors.
For some, 9/11 proves that
non-state groups can perpetrate attacks that reach the gravity threshold in any
case.19 However, 9/11
was an exceptional event and non-state groups may engage
in low-intensity assaults over an extended period of time. The Court has
addressed the issue squarely but has on three occasions contemplated and
arguably implied the existence of the doctrine.20
2. Non-State Groups as Perpetrators of an Armed Attack
In addition to the gravity threshold there is also the matter of which entities may perpetrate an armed attack. Discussion about the best answer to this question is the subject of the later parts of this article. A full analysis of the ICJ’s jurisprudence on this point will provide the basis for that discussion and help to set the debate in its conceptually difficult context. Klabbers argues that international law has been unable to seriously incorporate non- state actors into its framework.21 The problem is particularly stark in relation to art 51 and the self-defence right. Up to the 1945 San Francisco Conference, wars were generally initiated by military incursions by one state into the territory of another, underscored by formal declarations of war.22 As Franck comments, modern warfare has “inconveniently bypassed these Queensbury- like practices.”23 Article 51 was not designed to cope with non-state actors and therefore attempts to apply it in that context are fraught with difficulty. This is apparent in the ICJ’s two cases on point, the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion (the Wall Opinion)24 and the Armed Activities decision.
The Wall Opinion concerned Israel’s construction of a security
barrier in the Occupied Palestinian Territory to protect itself from terrorist
attacks being launched from the West Bank. Israel claimed to be acting pursuant
to art 51 and Security Council Resolutions 1368 and
1373.25 The Court dealt
with the self-defence claim like this:26
Article 51 of the Charter thus recognizes the existence of an inherent right
of self-defence in the case of armed attack by one state
against another state.
However, Israel does not claim that the attacks against it are imputable to a
Thus the Court disposed of the issue succinctly; if the group cannot be
attributed to a state, art 51 is not available. This appears
to reaffirm the
position in Nicaragua, requiring that non-state groups be sent “on
behalf ” of a state before self-defence is engaged.27 The restatement
the Wall Opinion has been described as “the most disappointing
aspect of the judgment”.28 However, other commentators have defended the
advisory opinion on the basis that it was not the right place to conduct a full
discussion of the self-defence doctrine.29 Even so,
the lack of reasoned
explanation did little to alleviate the “conceptual helplessness”30
with which international law
has approached non-state actors. The situation was
not improved by the Court’s next decision on the topic, the Armed
Activities case. Armed Activities concerned the legality of
Uganda’s incursions into the territory of the Democratic Republic of the
Congo (the DRC) in response
to a series of attacks perpetrated on its soil by
the Lord’s Defence League (the ADF), a non-state group, operating from
the territory of the DRC. After a thorough discussion of the admittedly
complicated factual background to the case, the Court made
For all these reasons, the Court finds that the legal and factual
circumstances for the exercise of a right of self-defence by
Uganda against the
DRC were not present. Accordingly, the Court has no need to respond to the
contentions of the Parties as to whether
and under what conditions contemporary
international law provides for a right of self-defence against large-scale
attacks by irregular
This writer interprets the statement to mean: Article 51 cannot be used against non-state actors, accordingly there is no need to consider whether Article 51 can be used against non-state actors. The words “for all these reasons” hint at some preceding legal analysis of the law of self-defence but actually refer to the Court establishing, at length, that attribution of ADF activities to the DRC could not be made out.32 There was no mention of the recent Wall Opinion precedent or an equivalent clear statement of the legal position;33 the place of non-state actors has been described as “the elephant in the room” of the judgment.34 While it is unfashionable to defend the Armed Activities decision, criticism of it is not entirely fair. The Court did at least impliedly answer the non-state actors question in the negative, rather than leave it open. Further, some justification was provided when the Court stated that art 51 operated within strict confines and could not be deployed to protect perceived security interests beyond those confines.35 This part of the judgment, while regrettably brief, is rarely quoted by critics. By contrast, Judges Kooijmans and Simma did consider the issue more fully in their Separate Opinions. Both judges expressed concern at the majority’s restrictive approach and emphasised changes in state practice and opinio juris as they relate to self-defence against non-state actors,36 the absence of a state attribution requirement within the text of art 5137 and the general principle that states should be permitted to defend themselves.38 These claims are responded to below.39
The Court was clear in both the Wall Opinion and Armed Activities that art 51 can only be used to respond to attacks by other states. However, the concept of attribution provides an avenue for the use of self-defence against non-state actors, if their activities can be attributed to a state. The test for attribution was articulated in Nicaragua as “effective control.”40 The standard is demanding. Although the Court in Nicaragua found that the United States largely “financed, trained, equipped, armed and organized [the Contras],”41 even a “preponderant or decisive” role in such assistance, going as far as to include the selection of targets, was not sufficient to attribute the conduct of the contras to the United States.42 To show attribution, the United States would have needed effective control over the particular contra military operations in the course of which the alleged violations were committed.43
This approach received some useful judicial scrutiny from the International
Criminal Tribunal for the Former Yugoslavia (the ICTY)
in the Tadić
case.44 In that case, the Appeals Chamber was called to determine whether a
conflict was international in nature, requiring it to
determine whether certain
Bosnian Serb units were acting on behalf of the Federal Republic of Serbia or
otherwise. In a thoughtful
judgment, the Appeals Chamber accepted that the
“effective control” test would be appropriate for individuals but
a lower standard of “overall control” was sufficient for
organised groups to be attributed to a state.45 The ICJ appeared
umbrage at these comments from a mere ad hoc tribunal and seized the opportunity
to reaffirm Nicaragua in the Genocide Case.46 The Court objected
to the Tadić standard because it amounted to: 47
... broadening the scope of State responsibility well beyond the fundamental
principle governing the law of international responsibility:
a State is
responsible only for its own conduct, that is to say the conduct of persons
acting, on whatever basis, on its behalf.
Thus the Genocide Case affirmed “effective control”
attribution as the only mechanism by which self-defence on the territory of a
can be lawful.
C. Necessity and Proportionality
In addition to the armed attack requirement, the responses of the victim state are regulated by the principles of necessity and proportionality. These principles are accepted as rules of customary international law relating to the exercise of the self-defence right48 yet do not appear in art 51.49 Nonetheless they form part of the law of self-defence, as regulated by both the United Nations Charter and by customary international law.50 The origin of the necessity and proportionality requirements is often traced to the exchange of letters between Secretary of State James Webster and Lord Ashburton, British representative to the US, concerning the Caroline, which occurred following the sinking of that ship by British forces in 1837. In the course of the letters the need to respond in self-defence was described as “leaving no choice of means,” which can be interpreted to mean that “[a] State can use force in self-defense only if there is no other option open to it to defend itself ”.51 The proportionality limb derives from Webster’s statement that “the act justified by the necessity of self-defense must be limited by that necessity, and kept clearly within it,” making the question one of balancing the response with defensive aims.52 Judge Higgins’ comments in her Dissenting Opinion in Nuclear Weapons support this notion of defensive necessity, endorsing Professor Ago’s statement that there is no requirement for symmetry between the attack and response.53
Despite their importance, the meanings of the two principles are often confused. The lay meaning of necessity, meaning to do only what is needed, actually describes jus ad bellum proportionality. Further, there is some unhelpful duplication in terminology as proportionality is used in both the jus ad bellum and jus en bello contexts. This has led some legal academics to provide ambiguous definitions.54 In the face of this confusion, the ICJ has within its self-defence jurisprudence devoted a total of four paragraphs out of many hundreds to these two principles. Only the comments in Armed Activities relate directly to self-defence action against non-state actors but the statements in Nicaragua and Oil Platforms apply indirectly to non-state actors, and so are discussed here. Beginning with the Court’s decision in Nicaragua, as the activities of the Contras were not attributable to the United States, the Court’s analysis related to those actions taken by the United States directly, including the laying of mines in Nicaraguan waters and attacks on Nicaraguan ports and oil installations. The Court found that the actions were taken months after the armed opposition against the government of El Salvador, which it was alleged Nicaragua was assisting, had been “completely repulsed.”55 On this basis, there was no necessity for the United States to “defend” El Salvador by attacking Nicaragua. While the Court classified the issue as one of necessity, it was really a matter for the proportionality analysis. As to proportionality as the Court saw it, while the “exact scale” of aid provided to the Salvadorian rebels by Nicaragua was unknown, United States military action against Nicaragua was not proportionate to it.56
The two concepts were further interpreted in Oil Platforms, where the
Court stated that, in the absence of evidence that the United States had
complained to Iran about the alleged military
activities of its oil platforms,
the United States’ military operations against those platforms could not
be said to be necessary.57
That is to say, military action was not the
“last resort.” On proportionality, the ICJ held that the response to
attack on the Sea Isle City (Operation Nimble Archer) might
have been proportionate had necessity been made out.58 However, the same
could not be said of the response to the attack on the USS Samuel B Roberts
(Operation Praying Mantis). The ICJ was influenced by the fact that the
operation involved the destruction of Iranian naval vessels
and aircraft as well
as attacks on the oil platforms but even that limited part of the operation was
not proportionate to the mining
but not sinking of a single warship, with no
loss of life.59 Finally, both concepts were mentioned in Armed
Activities. Although the Court did not consider whether the ADF had actually
perpetrated an armed attack against Uganda, the majority did provide
obiter statement on necessity and proportionality:60
The Court cannot fail to observe, however, that the taking of airports and
towns many hundreds of kilometres from Uganda’s border
would not seem
proportionate to the series of transborder attacks it claimed had given rise to
the right of self-defence, nor to
be necessary to that end.
While the meaning of “necessary” in this statement is uncertain,
it is clear that proportionality involves a qualitative
assessment of the action
taken in response to the armed attack. In Nicaragua, the use of military
force against Nicaragua was qualitatively disproportionate to the mere
provision of aid to the Salvadorian rebels, even without knowing the exact level
that aid. The same principle is at work in the Court’s pronouncements
in Oil Platforms and Armed Activities. Despite the absence of a
judicial definition, the notion of necessity as “last resort” and
proportionality as “defensive
necessity” clearly emerges from the
The International Court of Justice’s art 51 analysis, while lacking in
some respects, does provide useful standards against
self-defence actions can be evaluated. Direct consideration of the applicability
of art 51 in situations involving
non-state actors is limited to the Wall
Opinion and the Armed Activities case. The Court was clear in both
these cases that art 51 cannot be expanded to permit self-defence responses
against non-state actors
on the territory of other states. However, the lack of
fully-reasoned argument in support of this restrictive approach to art 51
exposed the law to misunderstanding and manipulation, including the reading down
of the case law and of art 2(4) itself. Most
prominently, pro-expansion scholars
point to the lack of analysis of state practice in the case law and claim a
shift in customary
III. Evolution? State Pr actice and Opinio Juris After
As the previous section demonstrated, the ICJ case law on self-defence has so far not included the depth of reasoning which might be expected from a Court of its stature. This situation has made it easier for commentators to criticise the Court’s position on non-state actors as restrictive and unfair. As Judge Kooijmans put it in his Separate Opinion in Armed Activities, “[i]t would be unreasonable to deny the attacked State the right to self- defence merely because there is no attacker State, and the Charter does not so require”.61 Kammerhofer points out that this is “a political motivation for a future change in the law, rather than reasoning to show how and by what means the law has changed.”62 That reasoning, although it is rarely made explicit by theorists, can be found in the notion of customary international law. A number of instances of post-9/11 state practice show that states have not been hesitant to assert a self-defence right against, in particular, terrorist groups, especially when host states have been unwilling or unable to suppress the activity themselves. When considered along with opinio juris, this practice is said to show that customary international law has evolved to allow for the existence of the expanded right.63 The ICJ, the pro-expansion scholars claim, is yet to catch up with dynamic customary law in this area.
Identifying the dividing line between state practice and opinio juris,
while of academic interest, is a largely fruitless exercise, connected to the
broader issue of whether custom provides a satisfactory
basis for the
development of the law. There is not space here to discuss those questions.
Therefore, for the purposes of this article,
state practice means the military
activities of states on the territory of other states while opinio juris
refers to the opinions of states, reflected in the views of UN organs and
international organisations, about the legality of those
Wherever the line is drawn, some basic principles can be distilled from the case
law, in particular the North Sea Shelf case. For custom, the Court
required that states undertake particular conduct because they believe they are
“conforming to a
legal obligation” and further that this custom must
be “settled.”64 In the subsequent Fisheries Jurisdiction
case, the Court indicated that custom should be “common,
consistent and concordant.”65 The passage of a short period
of time, such
as the period following 9/11, is not in itself a bar to a rule becoming
customary. However, the Court has held that
“practice, including that of
States whose interests are specially affected, should have been both extensive
and virtually uniform”66
for a customary rule to arise. Although some
scholars argue that accelerated custom formation may occur following a
moment” or paradigm-shifting event,67 such a custom must be
consistent and extensive. In accordance with this standard, a brief
and assessment of several key post-9/11 incidents is provided below.68 These
case studies are not a comprehensive
record but rather a list of the incidents
most often relied upon by proponents of an expanded self-defence right. In light
fact that Operation Enduring Freedom marked the commencement of the War
on Terror, it is covered first and in depth.
B. Case Studies
1. Afghanistan: Operation Enduring Freedom
The United States’ 2001 military action against Afghanistan, Operation
Enduring Freedom, and the accompanying Security Council
Resolutions, are most
often cited as proof of the acceptance of an expanded right to self-defence.
Reinold argues that international
acquiescence in Operation Enduring Freedom
was of itself sufficient to “call into question” the rules governing
of force and for the Nicaragua standard to “lose its validity
as the yardstick for what constitutes an armed attack.”69 No detailed
for the invasion of Afghanistan was made public but the
letter provided by Permanent Representative John Negroponte to the Security
Council on the eve of Operation Enduring Freedom does make clear the general
basis for the action:70
The attacks on 11 September 2001 and the ongoing threat to the United States
and its nationals posed by the Al-Qaeda organization
have been made possible by
the decision of the Taliban regime to allow the parts of Afghanistan that it
controls to be used by this
organization as a base of operation. Despite every
effort by the United States and the international community, the Taliban regime
has refused to change its policy. From the territory of Afghanistan, the
Al-Qaeda organization continues to train and support agents
of terror who attack
innocent people throughout the world and target United States nationals and
interests in the United States and
The statement contains a nod to the “last resort” necessity requirement in the claim that “every effort” was made to have the Taliban change its policy of harbouring Al Qaeda. No claim of direct attribution of Al Qaeda activities is made but Afghanistan is implicated for allowing its territory to be used as a base for terrorist activity. The inference to be drawn, in common with the other examples of state practice cited below, is that because Afghanistan failed to suppress the activities of Al Qaeda, the United States was forced to undertake that task itself. Nowhere in the letter is the Security Council advised that the United States was in fact undertaking a full-scale land invasion with the objective of regime change.71 Nonetheless, the Security Council is often said to have approved72 the use of force in Resolutions 1368 and 1373 and in doing so is said to have affirmed the existence of the expanded right.73 This view receives judicial endorsement in Judge Simma’s Separate Opinion in the Armed Activities case. The Judge indicated that the Resolutions amount to opinio juris and further “cannot but be read as affirmations of the view that large-scale attacks by non-state actors can qualify as ‘armed attacks’ within the meaning of Article 51.”74 This position is open to question on two grounds.
First, Security Council Resolutions are not generally regarded as reflective of opinio juris.75 The Security Council is a political institution, comprised of the victors of World War II and ten non-permanent members. It is “patently unrepresentative and undemocratic.”76 Second, the plain words of the Resolutions do not support the existence of an expanded self-defence right. A comparison with Resolution 661, passed in 1990 and regarded as approving the use of force to expel Iraq from Kuwait, is useful in considering the meaning of Resolutions 1368 and 1373. Resolution 661 provided that the Security Council was: “Affirming the inherent right of individual or collective self-defence, in response to the armed attack by Iraq against Kuwait, in accordance with art 51 of the Charter.” In contrast, references to either a triggering “armed attack” or to art 51 itself are notably absent from Resolutions 1368 and 1373. Further, the affirmation of the self-defence right appears in a preambular paragraph and is generic in nature.77 Both Franck and Gray claim that the generic affirming statement amounted to acceptance that the attack by Al Qaeda constituted an “armed attack.”78 With respect, that cannot be right. The Security Council had the opportunity on two occasions to classify the terrorist attacks as an “armed attack” and invoke art 51 but chose not to do so.79 It is a strain to regard two preambular references to self-defence as Security Council authorisation for a massive use of force,80 especially given the fact that the non-state perpetrators, Al Qaeda, or the host state Afghanistan, are nowhere mentioned.
As the United States’ letter to the Security Council makes clear, it
believed it was acting in accordance with its right to
self-defence, even though
the Security Council’s Resolutions are far more ambiguous. However,
the reactions of other organisations
do indicate support for Operation Enduring
Freedom. In a “rather unique demonstration of solidarity,”81 the 19
allies declared that they regarded the attacks as triggering art 5 of
the Washington Treaty, meaning that 9/11 was deemed to
be an attack against all
the NATO members,82 and subsequently directly affirmed their support for
Operation Enduring Freedom.83
Further, the Organisation of American States (OAS)
passed Resolutions expressing support for the United States and in October 2001
resolved that “the measures being applied...in the exercise of their
inherent right of individual and collective self-defence
have the full
support” of the OAS members.84 In contrast to the other examples cited
here, most states, including New Zealand,
supported the action in Afghanistan.
Commenting on this situation, Moir claims that Operation Enduring Freedom must
be considered lawful.85 International support for an
action does not make it lawful but it is fair to say that the consensus marked
the beginning of an opino juris in favour of the expanded right.
However, that consensus does not appear to have survived.
2. Russian Use of Force in Georgia
In 2002, Russia conducted a series of air raids on the Pankisi Gorge in Georgia, targeted against Chechen rebels and Al Qaeda terrorists believed to have set up camp in the region. Russia justified the operation in part on Georgia’s non-compliance with international counterterrorism obligations. In a letter sent to the United Nations exactly one year after 9/11, Russia stated that “[i]f the Georgian leadership continues to ignore Security Council Resolution 1373 and does not put an end to the bandit sorties and attacks on adjoining areas in the Russian Federation, we reserve the right to act in accordance with art 51 of the Charter”.86 There is no basis for an implied right to enforce Resolution 1373, which is concerned with non-forcible counterterrorism measures, or indeed any other Resolution. Clear language is needed to override the prohibition on the use of force, as enshrined in art 2(4). As to policy, implying a right of enforcement into Security Council Resolutions would make redundant those Resolutions that do authorise use of force and leave the Council cautious about resolving anything, lest it be seized upon as an authorisation. This leaves the notion of unwillingness or inability as a standalone justification for use of force. Reinold characterises the case as one of inability rather than unwillingness since Georgia did step up its own counterterrorism efforts in response to Russian pressure and indeed invited the United States to assist it in these efforts.87 The raids drew little international legal comment, although the violation of Georgian territory was condemned by the United States and the Parliamentary Assembly of the Council of Europe resolved that Russia should cease its military action and violation of Georgian territory.88 While instances of condemnation were limited, it is improbable that in remaining silent the rest of the international community meant to show support for a unilaterally determined right of self- defence on the territory of a state, especially given that Georgia was apparently cooperating with counterterrorism efforts.
3. Israel: Operation Change of Direction
In 2006, Israel launched a major offensive against Hezbollah fighters within Lebanon. The action was triggered by Hezbollah fighters ambushing an Israeli border patrol, killing three soldiers, wounding two and abducting two others. When read alongside preceding rocket attacks against Israel, the accumulation of events might see this attack classified as a qualifying armed attack. Israel responded with artillery, air and naval bombardment as well as a ground offensive in Lebanon. Operation Change of Direction would, the Israeli Army Chief of Staff warned, “turn back the clock” on Lebanon.89 Israel was at pains to categorise its actions as falling within art 51, seeking in its statements to attach “responsibility” to Lebanon for the Hezbollah attacks and denouncing Lebanon’s “ineptitude and inaction.”90 For Israel, the justification for use of force appeared to be Lebanon’s inability to prevent Hezbollah operations. Certainly there is little evidence of a greater level of responsibility for Hezbollah’s attack; the Lebanese government condemned the Hezbollah attacks and was not perceived, at least not by the United States, as a sponsor of terrorism.91
Opinio juris was mixed. While statements made in Security Council debates indicated support for Israel’s invocation of art 51 amongst most Council members, the Council did pass a Resolution calling for an end to violence on both sides and did not classify Hezbollah’s actions as an armed attack.92 The G8 issued a declaration acknowledging in principle Israel’s right to self-defence, the Secretary-General of the United Nations made a statement to similar effect and the United States Senate explicitly supported Israel’s exercise of the self-defence right.93 Direct criticism was aimed mainly at Israel’s disproportionate use of force but it is a stretch to draw the inference, as Van Steenberghe does, that states therefore did not contest Israel’s right to attack Lebanon.94 Further, beyond explicit support from the reliably sympathetic United States, the action garnered only “in principle” support, non-endorsement from the Security Council and express condemnation of “Israeli aggression” from the League of Arab States, with its membership of 22.95 This falls short of tacit international acceptance.
4. Turkey: Operation Sun
In December 2007, Turkey launched a major aerial bombing campaign against the
Kurdistan Workers’ Party (the PKK), based in Iraq.
This was followed by
major ground offensive in February 2008, Operation Sun. The PKK had perpetrated
numerous attacks against Turkish
military positions over several decades,
drawing responses from Turkey, but this particular incident was precipitated by
of especially bloody attacks in the later part of 2007. The government
of Turkey made limited public comment about the operation
and did not notify
the Security Council. As van Steenberghe points out, self-defence is the most
appropriate justification for
the incursion, given the absence of Iraqi consent
or Security Council authorisation,96 These comments support Tams’
that despite the diversity of state practice in the use of force
against non-state actors, self-defence is almost inevitably invoked
justification.97 A statement from the Presidency of the European Union
condemned the action: “While recognizing Turkey’s
need to protect
its population from terrorism, the Presidency calls on Turkey to refrain from
taking any disproportionate military
action and to respect Iraq’s
territorial integrity, human rights and the rule of law.”98 The
to Turkish activities was otherwise limited with no
resolutions being adopted by the Security Council, General Assembly or NATO
criticising Turkey’s conduct.99 Noting this, van Steenberghe argues that
“[t]aken together, international reaction to
the Turkish operation
strongly suggests that states in fact condoned this operation and thus did not
oppose Turkey’s right
to act in self-defence”.100 It is difficult to
see how a lack of reaction can be “taken together” to show that
states “condoned” Turkey’s action. In this case there is
insufficient evidence to determine an opinio juris.
5. Ecuador: Operation Phoenix
In March 2008, Colombian forces attacked members of the Revolutionary Armed Forces of Colombia (FARC) located within Ecuador, killing a top commander and other militants. Ecuador accused Colombia of violating international law in launching the attack while Colombia justified its action on the basis of self-defence against a terrorist group. The qualifying armed attack was not immediately apparent. Thus the legal basis for Operation Phoenix was uncertain but reliance was placed on a combination of inability and unwillingness on the part of Ecuador to disrupt FARC activities. The Minister of Defence noted that Ecuador had taken a position of not wanting to interfere in the conflict between Colombia and FARC but stated that if there had been greater cooperation from Ecuador in the pursuit of FARC, “this type of situation would not have arisen.”101 The Security Council and General Assembly did not comment on the action but various states in the region denounced it102 and the 35-member OAS adopted a Resolution in which it declared the action to be a violation of Ecuador’s sovereignty.103 The Resolution affirmed the principle that: “the territory of a state is inviolable and may not be the object, even temporarily, of military occupation or of other measures of force taken by another State, directly or indirectly, on any grounds whatsoever.”104 The response of the OAS illustrates the difficulty in identifying a consistent opinio juris on the non-state actor issue; as Reinold observes, its 2008 statement “stands in marked contrast” to the Resolution it adopted post-9/11.105
6. Pakistan: Operation Enduring Freedom Continues?
The most recent example of the expanded self-defence right being relied upon, as alluded to in the introduction to this article, is the United States’ targeted killing programme in Pakistan. Commencing in 2004, the programme is still active. It takes the form of strikes by Unmanned Aerial Vehicles (UAVs) against militants and, on at least the occasion of Osama bin Laden’s death, manned helicopter missions into Pakistani territory. Pakistan has made strong public protests about these military operations. However, there are reports that Pakistan does consent to the UAV strikes on an unofficial basis and assists with targeting of militants106 but in the absence of official acknowledgment, this can hardly provide a legal basis for the strikes. Instead, it is inferred that the United States turns, as in the other examples considered above, to the principle that where states fail to suppress non-state groups themselves, those states are automatically susceptible to military intervention.
The United States does not recognise Pakistan as a failed state as such107 but the “Af-Pak” border region at least is not under the full control of the Pakistani government. The United States perhaps claims a right to intervene in the Federally Administered Tribal Areas (FATA), an area not generally controlled by the government of Pakistan but loosely linked to Islamabad by means of a “political agent.”108 Even if this is so, the difficulty is that the United States undertakes many operations outside the “lawless” FATA, notably the killing of bin Laden in Abbotobad, located on the other side of Pakistan. Instead, it seems a wide-ranging right to undertake UAV strikes across all of Pakistan is claimed. In an effort to provide some form of legal framework for this activity, Ashley Deeks, a former Assistant Legal Adviser at the Department of State, points to several requirements which must be met for a state to determine that military intervention is necessary.109 Deeks relies on but does not cite state practice in support of these criteria.110 The requirements are that the acting state: (i) ask the territorial state to address the threat itself; (ii) reasonably assess the state’s control of the territory from which the threat emanates; (iii) reasonably assess the state’s proposed means to suppress the threat; and (iv) evaluate prior interactions with the state.111 Somewhat conveniently, Deeks locates an exception to the first requirement in situations where “the acting state has strong reasons to believe that the territorial state is colluding with the non-state actor, or where asking the territorial state to take steps to suppress the threat might lead the territorial state to tip off the non-state actor before the acting state can undertake its mission.”112 This rationale does represent an improvement from mere assertion of legality as relied on by others113 but leaves many questions, not least the legal source of the rationale, unanswered.
With the exception of condemnation from Pakistan, the international response
to the ongoing UAV campaign has been muted, making
its contribution to
customary international law hard to ascertain. It may be that the programme is
seen as an extension of Operation
Enduring Freedom, launched in the midst of an
outpouring of support for the United States after 9/11. That event may be the
attack which triggered the right to use force, or the United States may
rely on a series of attacks perpetrated from Pakistan as
evidence of an
accumulation of events but neither position has been subject to international
criticism to any great extent. The unsavoury
nature of some of the people
targeted also has the effect of limiting criticism, especially in the case of
Osama bin Laden. Deeks
opines that “[t]he facts and politics in this case
make it unlikely that Pakistan’s defense of its sovereignty will find
significant international support.”114 This is, of course, not the same
thing as claiming that the actions of the United
States are lawful.
On the basis of the incidences described above and a handful of pre-9/11
examples, some scholars argue that the restrictive reading
of art 51 is
“not consistent with state practice.”115 It is argued here that the
state practice does not disclose a
change in custom. First, on any measure, the
number of states which have engaged in extraterritorial self-defence is small
a non-representative group of world or regional powers. Second,
the military actions have occurred in entirely different contexts,
from a single
attack on a narcotics and terrorist group located a short way inside the border
in the case of Ecuador to an aerial
bombing in the case of Lebanon and a
full-scale invasion in the case of the United States in Afghanistan. As Tams
practice has been “marked by its diversity”116 rather
than uniformity. Nonetheless, some commentators are unfazed by
As is the case for most customary law on the jus ad bellum norms, it
is not possible to demonstrate through widespread and systematic state practice
that the concept of self- defense embraces
action against non-state actors, but
the better view appears to be that it does.
The legal basis for this claim is weak. In addition to the limited state
practice, a major difficulty is that the practice does not
parameters of the expanded right. Although the notion of a host state being
unwilling or unable to suppress terrorism
is often alluded to, what this means
in practice is left unsaid. On one interpretation, all of the states above
were simply unable
to prevent non-state groups operating from their territory.
Yet as Ruys observes, such a “strict liability” standard
to absurd results; for example, Spain using force against ETA terrorists in the
south of France or EU States striking
against members of the Kurdish DHKP/C
operating from Brussels.118 It cannot be that states are subject to military
action on their
territory even when they are making bona fide efforts to
suppress attacks. If the standard is more than mere tolerance or inability
act, the question arises as to where the line should be drawn. For instance, Al
Qaeda was “supported by the Taliban regime”119
but the nature and
level of support was not explained. In addition to this lack of consistent state
practice, the opinio juris on the events cited above is, at best, patchy.
Even if the pronouncements of the Security Council, the highly influential but
UN organ, are classed as opinio juris, no endorsement of the
expanded right emerges. As Murphy notes, uses of force not explicitly condemned
by the Security Council should
not be regarded as permissible.120 In summary,
a review of recent state practice and opinio juris sees no pattern emerge
in favour of the expanded right and reassures that, in the eyes of states, art
2(4) is not yet bereft of life.
IV. Alternative Legal Mechanisms for an Expanded
Customary international law, it is argued above, does not provide an avenue
by which the expanded right can be said to have come into
being. As Waxman has
written, the accretion of custom in the area of self-defence against non-state
actors is heavily disputed
owing to the divergent views interpreters hold of
the “basic structural attributes” of the antagonist actor, that is,
its linkages to the host state.121 Consequently, some commentators have
developed alternative mechanisms by which the expanded right
could be found to
exist, without having to rely on state practice. These approaches also allow the
appropriate threshold to be expressed
with greater clarity than can be divined
from the limited information and inconsistent behaviour which characterises
They provide clear legal mechanisms by which the ICJ could find
an expanded right to self-defence whereas the customary law option
a volte-face and blunt declaration that custom had left the Wall Opinion
and Armed Activities behind.122 The three options presented below
involve, respectively, a reading down of art 2(4), a reading down of the ICJ
or the modification of the attribution threshold. The first two
options will be shown to be unsatisfactory but the third, while unlikely
appease pro-expansion scholars, would represent a moderate and useful
B. Barbour and Salzman: Shrinking Sovereignty
Writing in the context of the Armed Activities decision, Barbour and Salzman argue for an approach to self-defence against non-state groups that focuses on the particular problem of the failed state. The suggested model applies only where a non-state group can be said to control territory but would nonetheless have application in several of the examples of state practice cited in this paper. In the authors’ view, if a non-state group controls territory, the state’s integrity is already compromised to such an extent that self-defence action within the state is not a violation of its territorial integrity.123 This is an altogether more radical position than that generally adopted by pro- expansion theorists, whereby a failure to prevent armed groups operating from territory acts as a kind of justification excusing a territorial violation undertaken in self-defence. Instead, the state is classed as no longer having any territorial integrity of which to speak. The authors do not spell out whether this loss of sovereignty applies just to the particular area controlled by the non-state group or to the territory of the state as a whole. If it is the former, the approach might allow military action against militants in the FATA but not, for example, in Abbotobad. If it is the latter, the entire state would effectively be outlaw country.
The idea that a state can be found to have “forfeited its right to
territorial integrity”124 is a novel one and represents
reading down of art 2(4). Article 2(1) of the Charter lays out sovereign
equality between states as the very foundation
of the United Nations. As Ruys
comments, failed and failing states are still sovereign and protected by the
principle of non-intervention.125
Security Council Resolution 1816, relating to
piracy off the coast of Somalia, is telling in this regard. The Resolution
states cooperating with the Somalian government to enter that
state’s territorial waters for the purposes of repressing acts
recognising that the state did not have the capacity to do so itself. In effect,
Somalia had lost control of its territorial
waters to pirates. However, the
Council affirmed that the Resolution applied only to Somalia and
“underscores in particular
that it shall not be considered as establishing
customary international law” and that it was passed only following
of consent by the Somalian government.126 The Security Council did not
accept that Somalia’s failed status meant it had forfeited
sovereignty, but relied instead on consent from the state and agreement between
Council members. This must be correct. To hold
otherwise would be a licence for
unregulated intervention by any state in the territory of any failed state.
There is also the practical
problem that no linear distinction can be drawn
between failed states, which are apparently stripped of their sovereignty, and
states. Although Barbour and Salzman emphasise failed states, the notion
of loss of control also applies to states which would not
be classed as failed,
such as Pakistan.
C. Trapp: “Back to Basics”?
The second legal mechanism discussed here is the “back to basics” framework proposed by Trapp, who argues that the debate about the right of self-defence against non-state actors rests on a misunderstanding of the ICJ’s decisions. According to Trapp, the ICJ position is not that state attribution is required to respond to non-state actors. Rather, attribution is required only if the host state itself is to be attacked. In support, Trapp notes that the Wall Opinion and Armed Activities both involve self-defence action directed more broadly than just the respective non-state groups.127 Trapp argues that rather than focus on the attribution of an armed attack, the guiding principle should be necessity. When a host state is unwilling or unable to suppress non-state groups, the victim state is left with “little choice” but to intervene itself.128 Mere acquiescence is said to “account for the necessity of the defensive use of force.”129
There are four difficulties with Trapp’s approach. First, while that reading of the case law provides an ingenious way around the precedents, it is a stretch to argue that the ICJ was making as sophisticated a distinction as Trapp maintains. Green writes that there is no basis for locating such a distinction and the use of the phrases “by or on behalf of ” in Nicaragua and Armed Activities, and “imputable” in the Wall Opinion show that the ICJ does require attribution to the state itself before a self-defence response can be undertaken.130 Second, such a distinction makes little practical difference to host states. The model does not recognise that even if military action is directed only against the non-state targets, the sovereignty of the state itself is offended by the conduct of military activity on its territory. Contrary to Paust’s statement otherwise, it is extremely difficult to use self-defence measures “merely” against the non-state group131 because, as recent history shows, self-defence responses tend to wreak destruction on a broader scale.
The third and fourth difficulties relate to Trapp’s reliance on the
necessity criterion. It is suggested here that necessity
alone falls far short
of justifying self-defence action on the territory of another state.
Trapp’s argument is essentially
that a state unwilling to prevent
non-state actor activities is, through the necessity component, automatically
territorial incursion, subject to the proviso that
proportionality requires that only the non-state group be attacked directly.
appealing, there is a conceptual sleight of hand in this approach which
involves shifting the “subject” of the three
criteria around. Thus
the armed attack is perpetrated by a non-state group yet the necessity criterion
is applied only against the
state (the notion being that its unwillingness to
stop the attacks makes use of force against it necessary) and the
criterion is applied against both the state and the non-state
group. In a standard art 51 situation, all three elements are applied
same entity (the state). Trapp’s approach is incoherent because the
logical link between the attacker and the entity
responded against is still
missing. Finally, as the discussion above indicated,132 the very meaning of
necessity is the subject
of uncertainty and confusion. Trapp herself, having
defined necessity as related to the availability of alternatives to the use
force,133 subsequently appears to use it in a rather broad justificatory sense:
acquiescence in the face of terrorism is said
to “account for”
necessity.134 Placing the conceptual burden on this one factor will require that
a clearer definition
be established. Thus while purporting to go “back to
basics,” Trapp ultimately fails to justify breaching the basic rule
D. Tams: Rethinking Attribution
As the discussion in Part II demonstrated, the “effective
control” standard for attribution of non-state actors set in
and reaffirmed in the Genocide Case is demanding. The application of
a rigid standard to all cases attracted criticism from the Appeals Chamber in
Tadić, which noted that the degree of control may vary from case to
case but there is no reason to require the high “effective control”
threshold in every situation.135 The difficulty is that attribution becomes an
“all or nothing” affair, unable to incorporate
more complex forms of
state involvement.136 If attribution cannot be demonstrated, the fact of a state
supplying the necessary resources
and training for the perpetration of an
attack counts for nothing in terms of permitting an armed response. Glennon
the implications of insisting on the effective control
... if the government of Afghanistan had directly provided the terrorists
with airplane tickets, funds for flight lessons, and the
box cutters used to
hijack the aircraft that crashed into the World Trade Center and the Pentagon,
or if the Afghan government had
provided the anthrax spores used to contaminate
the American postal system, such support would still not constitute an armed
and the use of force against the Afghan government would therefore not
have been permitted.
Such a high attribution threshold is not easy to defend and this author does not propose to do so. Rather, it is accepted here that Nicaragua should be revisited. Tams argues for an adjustment to allow non-state activities to be more easily attributed to states. This approach, he suggests, “retains the traditional understanding as a justification for the use of force between states but recognizes the existence of special rules on the attribution of terrorist activities.”138 In support, Tams claims that state practice shows a lower standard of attribution has emerged.139 Van Steenberghe contests this idea, arguing that states do not pitch their justifications in terms of “attribution”,140 which the state practice outlined above tends to support. Despite this reality, reconsidering the attribution threshold still provides the only legally defensible avenue for reform of art 51.
Considering Nicaragua, Cassese points out that the Court did not cite any authority for its effective control test.141 If the Court had reviewed relevant case law it would have found support for effective control only in situations where private individuals act on behalf of the state, not where organised groups are concerned.142 The ICTY Appeals Chamber in Tadić143 made this point and rejected the test as applicable in all circumstances, stating the test for organised groups as requiring that a state wield “overall control of the group, not only by equipping and financing the group but also by coordinating or helping in the general planning of its military activity.”144 Expressed slightly differently later in the judgment, the test requires that the host state “has a role” in organisation in addition to financing, training and equipping or providing operational support.145 This is a significantly less demanding standard than effective control and will be engaged in a broader range of fact situations. Cassese argues that the overall control test may turn out to be “particularly efficacious” in relation to state-harboured terrorist groups.146
However, it may be possible to find another useful standard within the
ICJ’s own case law. In Nicaragua, the Court adopted the phrase
“substantial involvement” in the course of defining an armed attack
as involving the “sending
by or on behalf of a state” the armed
group that carried out the attack or “substantial involvement”
While the Court ultimately laid down the effective control
standard and stated that financing and equipping a group did not
it, the substantial involvement standard could be “revived” and
given content by the Court in future. Ruys
argues that this approach,
“building on existing principles rather than abandoning the rules
altogether,” is the best
way to adapt to the contemporary security
context.148 Writing critically of Tams, Trapp argues that requiring attribution
more than a mechanism for maintaining an inter-state reading
of Article 51 and ensuring that defensive force is a true exception
prohibition on the use of force against the territorial integrity or political
independence of another state.”149 This
of course, is precisely
Tams’ point and why his proposal is the most conceptually sound of the
three considered in this section,
as well as being the only model that can be
supported by legal analysis. A modified attribution threshold provides a
way to better incorporate non-state groups in international
The discussion above has examined three possible mechanisms by which the
right to self-defence could be expanded. The first two of
these mechanisms have
been rejected. Barbour and Salzman’s suggested reading down of art 2(4) is
inconsistent with the fundamental
notion of sovereign equality and would be
unworkable. Trapp’s approach, while less radical, is no more coherent,
supply the connection between host state and non-state group that
might justify use of force. Reliance on a slender distinction between
directed against the non-state group exclusively and force directed against the
host state does not resolve this problem. By
contrast, Tams’ modified
attribution test, derived from the case law, is a defensible mechanism for
better recognising the
place of non-state actors. The retention of a relatively
high standard, requiring state involvement, avoids the policy concerns
arise when mere acts of omission, unwillingness and inability are deemed
sufficient to ground a self-defence response.
V. A Principled Defence of the Restrictive Approach
The oft-expressed and most intuitively appealing of pro-expansion arguments
is based on principle: states must be permitted to defend
themselves and it
should not matter whether attacks are perpetrated by other states or by
non-state actors. Glennon makes the point
If a host state is unable to unwilling to curtail harmful private conduct
when that conduct originates from within the host state’s
makes no sense to insist that the victim state remain indifferent to such
conduct, effectively sacrificing the integrity
of its own territorial
sovereignty for that of the host state.
The international legal system provides the art 51 exception, which does
not require Security Council authorisation, for use
in the narrow
circumstances affirmed by the ICJ. In all other situations, use of force can be
lawful, provided it is approved
by the Security Council. There are sound policy
reasons for the maintenance of the restrictive position.
A. Limiting Opportunities for the Use of Force
Limiting the use of force and the harm it entails is a valuable policy goal in itself. Paust’s reliance on the Caroline and pre-Charter state practice as evidence of the absence of a “consistent pattern of generally shared legal expectation” in support of a restrictive reading of art 51151 is misplaced. As Antonopoulous writes, unilateral resort to force was lawful in the 19th century and the plea of self-defence was not a limited exception to a legal prohibition.152 The legal situation changed with the advent of the Charter and its objective of saving successive generations from the “scourge of war.” It should be recalled that peace is “the big interest at stake”153 when interpreting the right to self-defence. The fundamental prohibition in art 2(4) is designed to protect this interest; after all “[t]he purpose of international law, like all law, is the peaceful settlement of disputes. Law substitutes for force in helping people resolve conflict.”154 Of the Armed Activities decision, Kammerhofer argues that it places the Charter at the centre of the legal world-view, with its primary goal of avoiding war as the “guiding light” in its interpretation.155 Insisting that violations of a state’s territory occur only when an attack is actually attributable to that state maintains art 2(4) as the guiding light in the jus ad bellum.
A slower resort to force would also provide the space for other international
mechanisms to operate. As Ruys stresses, the fight
against terrorism is
first and foremost a matter of law enforcement and should be dealt with through
there will be situations where this is not forthcoming
but use of force should be, as necessity requires, the last resort rather
the first. The mechanisms of international criminal law are arguably
underexploited. Terrorism was unfortunately not included
jurisdiction of the International Criminal Court157 but as Tams argues, the
future might hold a return to the demilitarisation
of terrorism and the creation
of a “terrorism chamber” to try suspects.158
B. Preserving the Rule of Law: Evidence and Oversight
As well as putting pressure on art 2(4), the expanded right tends to diminish
the rule of law. Given that there is no international
consensus as to what
level of state involvement triggers susceptibility to territorial violation,
allowing states themselves to
determine when the threshold is reached is
hopeless. In relation to the killing of Osama bin Laden, Deeks argues that
size and location of the [bin Laden] compound and its proximity to
Pakistani military installations has cast strong doubt on Pakistan’s
commitment to defeat Al Qaeda.”159 Alarmingly superficial judgements of
this nature highlight the risk that a general right
to use force against
non-state actors would have art 51 “fall prey to arbitrariness and double
standards”160 to a far
greater extent than occurs in state versus state
self-defence. Commenting on United States strikes against alleged terrorist
in Sudan and Afghanistan in 1998, Lobel writes:161
When one nation attacks another, the factual predicate for self-defense is
clear and observable. That is usually not the case where
a nation claims the
right to use force in response to alleged terrorist attacks and imminent threats
thereof. It is untenable for
one nation to attack another merely because it
alone claims that such a group operating in the other country is launching
attacks against it. ... Those who urge a looser interpretation of
Article 51 have yet to prescribe a viable method of ensuring that
characterizations of the facts are subject to some clear legal standard and
Along similar lines, O’Connell gives the example of the first Gulf War
as a situation where it was clear that Iraq was the source
of aggression against
Kuwait, indeed, Iraq was still in occupation of Kuwait when the United States
and allies invaded to expel
Iraqi forces.162 When the situation is less clear,
evidence of the host state’s activities and alleged
of the non-state group becomes crucial. Responding to
concerns about the need for evidence to be presented before the self-defence
right could be exercised post-9/11, Franck argues that “any attacked state
is likely to make an intense effort to demonstrate
the culpability of its
adversary.”163 Unfortunately, subsequent events have not borne out
this prediction. As Antonopoulous
notes, states that have used forced against
non-state actors have generally not taken the trouble to furnish evidence of the
nature of the host state’s involvement in their activities.164
Instead, states have essentially required the international
community to trust
them that some vague standard of inability or unwillingness has been met.
Reinold observes that “[i]nferences
about the ‘real’
intentions and capabilities of governments, especially in matters of national
security, are always
fraught with ambiguity.”165 It cannot be for states
to unilaterally make these determinations and commence action accordingly.
Franck writes, “a rule of law which permits a state to use force whenever
it thinks it has been attacked is not much of
Strikes against non-state actors are, it has been argued, necessarily more
complex matters than state versus state attacks. When
it is clear that peaceful
means are insufficient to manage the threat posed by a non-state group, art 51
should not be deployed to
fill the gap. It was not designed for such a purpose
and as the ICJ stated in Armed Activities, it does not permit the use of force
to protect perceived security interests beyond its strict confines.167 Instead,
a case should be presented to the Security Council.
The Somalia Resolutions 1816
and 1851 show that the Council has been prepared to authorise naval action
within the territorial waters
of a sovereign state, to suppress the
activities of non-state actors. While its post-1989 counterterrorist activism
primarily non-military,168 the Council does have the power to decide
whether an authorisation for the use of force, perhaps on the
basis that a state
must be brought into compliance with its counterterrorism obligations, is the
appropriate course of action.
C. Hard Cases Make Bad Law: the Nature of the Non-State Actor Threat
The nature of the threat posed by non-state actors, particularly the international terrorists who are the targets of the War on Terror, should be interrogated before the self-defence exception to the use of force, as it has been understood “for more than 50 years,”169 is expanded. Calls for change are often based on a particular notion about non-state actor activity. Paust offers an analogy involving a shooter firing a rifle from a neighbouring house and asks rhetorically whether consent would be required from the owner of that house before fire could be returned, or whether one would have to wait for the police to arrive.170 Quite apart from the Wild West overtones of the expected answer in the negative, the analogy is premised on the notion of a terrorist hiding in another state and firing across the border. The true nature of a group’s functional linkages with a particular state, and even whether it can be said to “operate from” a state at all, is a contested area of scholarship and has implications for the jus ad bellum.
There is not the space in this article to review the literature on that topic
but it is argued here that there is at least a mixture
centralised cross-border threats and more complex, dispersed cell-based
terrorist organisations. Antonopoulous
comments on the structure of Al Qaeda as
clandestine small groups of “next door” operatives who are capable
large-scale attacks at the level of a single cell.171 Such cells
may operate without linkages to the “host” state. As
“[a] terrorist threat’s structural fluidity or deconcentration may
be the source of its strength and resilience.”172
This is not to say
that cross-border threats of the traditional type do not exist, but rather that
the picture is complicated.
As Waxman puts it:173
Terrorist threats fitting either model co-exist, as do many threats in
between. Indeed, that is precisely the cautionary point: pegging
legal reform to
a static prediction about the structure and operation of non-state groups risks
constructing a rigid legal architecture
on a shifting or fleeting set of
A further difficulty is that terrorist activity is increasingly homegrown.
The 9/11 hijackers were Saudi Arabian yet crucial parts
of their preparation
were undertaken within the United States, notably learning to fly planes at a
Florida flight school. Therefore,
it seems unwise to widen the scope of art 51
based on contested understandings of the threat posed by terrorism. History
caution in this regard. The nature of various supposedly mortal threats
requiring extraordinary countermeasures has changed over
time from the days of
bandits and partisans to mutually assured destruction in the Cold War and now,
modern terrorism. The terrorist
threat has been a real one for many decades and
was previously addressed by a regime of international rules within which the
of force did not play a main role.174 9/11 has been variously described as a
paradigm-shift, a Grotian moment and a turning point
in history, generating
enthusiasm for military responses which are not permitted by international law.
Commenting on Armed Activities, Kammerhofer observes that the
majority’s message in that case “instils the calm rationality that
is so often lacking
in present-day discourse, a discourse in a permanent
rhetorical hype alleging a permanent state of exception.”175
It has been argued above that principle supports the restrictive meaning of
art 51. The ICJ approach will slow the resort to the use
of force and keep the
Charter’s fundamental prohibition on the use of force at the centre of
international law. It ensures
that states cannot deploy the self-defence
justification in furtherance of security objectives but rather only within the
confines set out by the Court. Any other situation requires a Security
Council authorisation, giving the international community
the opportunity to
apply appropriate scrutiny to states’ self-defence claims. This oversight
is essential for the maintenance
of confidence in the international system.
Further, a departure from the orthodox art 51 position should not be rushed into
basis of an inaccurate understanding of the nature of the threat posed by
non-state actors. After 9/11, a number of states and scholars
agitated for a
radically expanded jus ad bellum, reliant on a set of faulty principles. A
decade on, cooler heads can prevail.
VI. What is to be Done: Bringing the Law Back In
At the core of the principled reasons offered above is a concern with
restoring the status of international law as the primary regulator
of the use of
force, rather than a mere “disposable tool of diplomacy.”176 Recent
state practice and opinio juris indicates
that states have, to some extent,
given up on the language of law. Recognising that law has been squeezed out of
the non-state actor
debate, reaffirming its value, and acknowledging the role of
the ICJ, are steps towards bringing the law back in.
A. Using the Language of Law
While it is tempting to think so, 9/11 was not the point at which powerful
states abandoned the language of the law for notions of
what was right or
reasonable. Rather, the groundwork had been laid two years earlier, during
NATO’s intervention in Kosovo.
Although it was a humanitarian intervention
and not a self-defence action, the intervention is instructive for its
of the ease with which states come to “rest their case”
on matters other than the law, especially in situations of perceived
campaign in Kosovo was not approved by the Security Council but was described
as an “illegal but legitimate”
intervention.177 It is symbolic of
an international order in which, as Koskenniemi puts it, “what counts
as law, or humanitarianism,
or morality, is decided with conclusive authority by
the sensibilities of the Western Prince.”178 For others, this state of
affairs is less problematic. Simma, writing prior to his elevation to the ICJ,
suggests that cases such as Kosovo left states “with
no choice but to act
outside the law.”179 As Roberts comments, acting “outside the
law” is a euphemism for breaking
the law; the idea of
“technical” illegality downplays the reality of the art 2(4)
violation.180 Simma was aware of this
difficulty, warning that a NATO policy of
regular breaches of the UN Charter would be immeasurably destructive to the
system.181 Thus, all was well as long as Kosovo remained an
exceptional case. The difficulty, as Charlesworth argues, is that
are regarded as the “engine of progressive development” in
international law, the law becomes “simply
a source of justification for
the status quo.”182 In light of this insight, Simma’s stance on
Kosovo makes an interesting
prelude to his hawkish position on art 51 in
Commentary on the non-state actor debate often casts international law, just as in Kosovo, as a barrier to states doing what is reasonable or morally proper. Professor Anderson reels off a rogues’ gallery of “middling state powers, emerging great powers, outright enemies, idealistic NGOs, United Nations functionaries, law professors and intellectuals ... [who] seek to leverage their influence by using the rhetoric of international law to constrain U.S. flexibility.”183 He writes with apparent bafflement that “important actors ... do not even accept that the situations in which the United States has undertaken targeted killing in, for example, Pakistan constitute legitimate self-defense under the UN Charter.”184 The answer, it seems, is to simply not bother with the law. Rostow argues that when states are threatened, they will look to their ability to defend themselves, a reality which the law, “to be the law, must respect.”185 Maggs advises that the United States should disregard legal constraints on its behaviour before going on to, without irony, dismiss amending the Charter as impossible because “[o]nly the United States and a few other democracies both use military force to respond to terrorism and care about international law.”186
The idea of giving up on international law is an extreme one and states do
generally seek to justify their activities as falling
within a legal framework.
However, as Part III of this article demonstrates, states can be less than
forthcoming as to the legal
justification for their behaviour. The effect of
abandoning the law in favour of what is perceived as right, whether that is the
bombing of Kosovo or Pakistan, is that there is no longer a standard against
which state behaviour can be evaluated. A restrictive
international law can be criticised as “formalistic,”187 but as
Koskenniemi writes, formalism is
not without value:188
In the case of international law’s obsession about military crises, war
and humanitarianism, it is a politics by those who have
the means to strengthen
control on everyone else ... In such a situation, insistence on rules,
processes, and the whole culture of
formalism now turns into a strategy of
resistance, and of democratic hope. Why? Because formalism is precisely about
to the impulses – ‘moral’ or not – of
those in decision- making positions in order to fulfil general, instead
particular, interests; because it casts decision-makers as responsible to the
political community; and because it recognises
the claims made by other members
of that community and creates the expectation that they will be taken account
Formalism is, in this sense, the very language of law. Humanitarian
intervention saw states fall back to defences based on what
was moral and just
while self-defence rests on what is reasonable and just. Principles matter but
respect for the law is of itself
one of the most important of principles.
Getting states to speak the language of law rather than rely on what they
consider to be
reasonable is essential if the prohibition on the use of force is
B. The Place of the Court
The International Court of Justice has a crucial role to play in this
process. The Court needs to provide a more forthright and comprehensive
statement of the restrictive position on art 51, incorporating within it a
response to arguments based on custom and, especially,
the suggestion that the
expansive right is somehow more reasonable than the Court’s
interpretation. A reasoned defence of
the position would go some way to
restoring the Court’s credibility on the issue. Murphy suggests, with
reason, that it is
too much to expect international courts to lead the way in
this area.189 However, the ICJ and other institutions have much to offer.
the supreme world judicial institution, the ICJ’s panel of international
judges is in a position to say things that
states may not like. The Court
should make use of its privileged position. Higgins comments that it is, after
all, the Court’s
job to decide difficult and often sensitive points of
law.190 Undoubtedly its reputation has been harmed by its habit of
restating”191 its own views. The value of judicial
economy “cannot excuse an absence of reasoning nor can it provide
for avoiding issues simply because they are hard to resolve”192 but this
should not overshadow the value of judicial
dispute settlement in terms of
providing an authoritative and impersonal answer to legal questions and allowing
off ” period in which negotiations can take place.193 As
Part II of this article shows, the Court is able to set standards
state behaviour can be assessed, including considerations of gravity and the
application of the necessity and proportionality
principles, even if the result
requires a certain amount of academic interpretation. Bringing the law back in
to the self-defence
debate requires leadership from the ICJ. The Court should
make its voice heard.
This article has sought to present a robust defence of the orthodox restrictive position on the use of art 51. The law remains and should remain that declared by the ICJ. Customary international law has not developed to support the expanded right and state practice and opinio juris do not disclose a common standard at which point a host state becomes susceptible to incursion. Alternative technical bases for accepting a change in the law, involving the reading down of art 2(4) and the ICJ case law are equally unsatisfactory, although an adjustment to the attribution threshold may be warranted. A consideration of three important matters of policy shows that a limited self-defence exception is right in principle as well as law. Uses of force pursuant to the supposed expanded right have been characterised by unilateralism, an absence of Security Council approval or ICJ oversight and, beyond a small group of powerful states, mixed international support. It is as if, to borrow Franck’s analogy, “the law were to leave to the two drivers in a motor vehicle collision the sole responsibility for apportioning liability, helped only by the unruly crowd gathered around them at the scene of the accident.”194 The rule of law demands more.
The ICJ position may well be criticised as “overly schematized and scholastic”195 but it is submitted that this is preferable to an approach built on vague and unpersuasive notions of a change in custom, a disinterest in peaceful dispute resolution and careless assumptions about the nature of 21st century terrorism. Formalism’s “culture of restraint”196 would not go amiss in the jus ad bellum debate. Admittedly, the Court has itself failed to adequately explain and defend its own stance, giving oxygen to proponents of the expanded self-defence right. Acceptance of the expanded right would finally signal the death of art 2(4), some four decades after Franck first sought to identify its killers. Although art 51 remains the avenue of choice for powerful states seeking to achieve security and foreign policy objectives, the moral imperative of humanitarian intervention apparently having dimmed, the now quaint concerns of the Cold War have been replaced by an amorphous and indefinite threat posed by terrorists and the states that harbour them. This threat provides cover for powerful states to variously distort and disregard the rule of law in favour of informal standards of what is reasonable or right. All international lawyers should be dismayed to hear territorial integrity, and therefore the Charter itself, downgraded to a mere “consideration”197 in war-making.
As long as the global War on Terror continues, the international legal order
remains under threat. Without principled leadership from
states, the Security
Council, and the ICJ, a dangerously expanded conception of art 51 may become a
legal reality. If hard cases
make bad law, the rise of non-state actors may be
international law’s hardest case. When the ICJ has reason to consider the
issue afresh, it should seize the chance to be forthright. Far from being the
“dead parrot” of international law, it
is time for the Court to make
clear that art 2(4) was “just resting” all along.
* - BA/LLB (Hons) (Auckland). Crown Prosecutor at Meredith Connell. I wish to thank Treasa Dunworth, Max Harris and Patrick Lilly for their comments on a draft of this article.
1- Harold Koh “The Lawfulness of the U.S. Operation Against Osama bin
Laden” (2011) Opinio Juris
2 - Harold Koh “The Obama Administration and International Law” (Annual Meeting of the American Society of International Law 2010, Washington DC, 25 March 2010).
3 - Ibid.
4 - James Oliphant “Holder says Osama bin Laden shooting was ‘justified’” The Los AngelesTimes (United States, 4 May 2011).
5 - See discussion below under necessity and proportionality.
6 - Thomas M Franck “Who killed Article 2(4)?” (1970) 64 AJIL 809 at 835 and 837.
7 - Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America)(Merits)  ICJ Rep 14 at  [“Nicaragua”].
8 - Oil Platforms (Islamic Republic of Iran v United States of America) (Judgment)  ICJ Rep 161 at  [“Oil Platforms”].
9 - Nicaragua, above n 7, at .
10 - Ibid, at .
11 - Ibid.
12 - Ruth Wedgwood “The ICJ Advisory Opinion on the Israeli Security Fence and the Limits of Self-Defence” (2005) 99 AJIL 52 at 57.
13 - Oil Platforms, above n 8, at .
14 - See for example Dominic Raab “‘Armed Attack’ after the Oil Platforms case” (2004) 17 LJIL 719 at 724-725, William H Taft IV “Self-Defence and the Oil Platforms decision” (2004) Yale J Intl L 295 at 300-301.
15 - Oil Platforms, above n 8, at .
16 - Ibid, at .
17 - The Court’s subsequent reference at  to the fact that the USS Samuel B. Roberts was “severely damaged but not sunk, and without loss of life” provides an indication in this direction. If the writer’s inference is correct it is likely that, for example, the attack perpetrated by Al Qaeda against the USS Cole in 2000, in which 17 sailors were killed, would satisfy the gravity threshold.
18 - Armed Activities on the Territory of the Congo (Democratic Republic of Congo v Uganda) (Judgment)  ICJ Rep 168 at  [“Armed Activities”]. Judge Kooijmans did consider the issue directly in his Separate Opinion at , holding that the five rebel attacks perpetrated in Uganda over a two month period amounted to an armed attack.
19 - James A Green The International Court of Justice and Self-Defence in International Law (Hart Publishing, Oxford, 2009) at 44.
20 - See Nicaragua, above n 7, at , Oil Platforms, above n 8, at  and Armed Activities, above n 18, at .
21 - Jan Klabbers “(I Can’t Get No) Recognition: Subjects Doctrine and the Emergence of Non-state actors” in Jarna Petman and Jan Klabbers (eds) Nordic Cosmopolitanism: Essays in International Law for Martti Koskenniemi (Martinus Nijhoff Publishers, Leiden, 2003) 352 at 354.
22 - Franck, above n 6, at 812.
23 - Ibid.
24 - Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territor (Advisory Opinion)  ICJ Rep 136 at  [“Wall Opinion”].
25 - Ibid, at . The status of the Security Council Resolutions is discussed in detail at page 20 of this paper.
26 - Ibid, at .
27 - Nicaragua, above n 7, at .
28 - Susan Breau “Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory: Advisory Opinion, 9 July 2004” (2005) 54 ICLQ 1003 at 1007.
29 - Ian Scobbie “Words my Mother Never Taught Me – in Defence of the International Court” (2005) 99 AJIL 76 at 87.
30 - Klabbers, above n 21, at 354.
31 - Armed Activities, above n 18, at .
32 - Ibid, at  to .
33 - Murphy argues that Armed Activities represents a “possible retreat” from the Wall Opinion, see Sean D Murphy “The International Legality of US Military Cross-border Operations from Afghanistan into Pakistan” (2009) 84 Intl L Studies 18 at 34. In the writer’s view the absence of a Wall Opinion-style statement in Armed Activities more likely reflects a lack of coherency in reasoning rather than a change of heart by the ICJ.
34 - Stephanie A Barbour and Zoe A Salzman “The Tangled Web’: The Right of Self-Defence against non-State Actors in the Armed Activities Case” (2008) 40 NYU JILP 1 at 83.
35 - Armed Activities, above n 18, at .
36 - Ibid, Separate Opinion of Judge Simma, at , Separate Opinion of Judge Kooijmans, at .
37 - Ibid, Separate Opinion of Judge Kooijmans, at .
38 - Ibid, at .
39 - See below.
40 - Nicaragua, above n 7, at .
41 - Ibid, at .
42 - Ibid, at .
43 – Ibid
44 - Prosecutor v Dusko Tadić (Judgment) ICTY Appeals Chamber IT-94-1-A, 15 July 1999 [“Tadić ”].
45 - Ibid, at .
46 - Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v. Serbia and Montenegro) ( Judgment)  ICJ Rep 43 [“Genocide Case”].
47 - Ibid, at .
48 - Legality of the Threat or Use of Nuclear Weapons (Advisory Opinion)  ICJ Rep 226 at  [“Nuclear Weapons”].
49 - However, the fact that they apply is not seriously questioned. This state of affairs rather undermines the common pro-expansion argument that because art 51 does not require the attack be perpetrated by a state, it can therefore be used against terrorists. See, for example, Armed Activities, above n 18, Separate Opinion of Judge Kooijmans, at  and Wall Advisory Opinion, above n 25, Dissenting Opinion of Judge Higgins, at .
50 - Nicaragua, above n 7, at .
51 - James A Green “Docking the Caroline: Understanding the Relevance of the Formula in Contemporary Customary International Law Concerning Self-Defense” (2006) 14 Cardozo J of Intl and Comp L 429 at 451.
52 - Ibid, 462.
53 - Nuclear Weapons, above n 48, Dissenting Opinion of Judge Higgins, at .
54 - See for example Mary Ellen O’Connell “The International Law of Drones” (2010) 14(36) ASIL Insights Issue 36 at 3, where the author cites Nicaragua and Nuclear Weapons as authority for the statement that “there is no right to use force in self-defense if the use of force is not necessary to accomplish the purpose of defense and/or the purpose cannot be accomplished without a disproportionate cost in civilian lives and property.” The concepts O’Connell refers to here are, respectively, jus ad bellum proportionality and jus en bello proportionality. Loss of civilian lives will be of incidental relevance to the right to use self-defence but would not make it unlawful at the jus ad bellum level.
55 - Nicaragua, above n 7, at .
56 - Ibid.
57 - Oil Platforms, above n 8, at .
58 - Ibid.
59 - Ibid, at .
60 - Armed Activities, above n 18, at .
61 - Armed Activities, above n 18, Separate Opinion of Judge Kooijmans at .
62 - Jorg Kammerhofer “The Armed Activities Case and Non-State Actors in Self-Defence Law” (2007) 20 LJIL 89 at 113.
63 - Judge Simma is a judicial proponent of this notion, see his Separate Opinion in Armed Activities, above n 18 at .
64 - North Sea Continental Shelf (Judgment)  ICJ Rep 3 at .
65 - Fisheries Jurisdiction (United Kingdom v Iceland) (Merits)  ICJ Rep 3 at .
66 - North Sea, above n 64, at .
67 - Michael P Scharf “Seizing the ‘Grotian Moment’: Accelerated formation of Customary International Law in Times of Fundamental Change” (2010) 43 Cornell Intl LJ 439 at 446.
68 - There are a number of examples of pre-9/11 use of force against non-state actors, a number of which were undertaken by the United States, but it was with the advent of the War on Terror that calls for an expanded right to self-defence became most prevalent.
69 - Theresa Reinold “State Weakness, Irregular Warfare, and the Right to Self-Defense Post-9/11” (2011) 105 AJIL 244 at 252.
70 - Letter from John Negroponte, Permanent Representative of the United States of America to the United Nations Security Council, to the President of the Security Council regarding the initiation of action in exercise of its inherent right to individual and collective self-defence in response to the terrorist attacks of September 11, 2001. See UN Doc S/2001/946 (2011) [“Negroponte”].
71 - Although this is an issue of proportionality rather than a question of whether the force was permitted at all.
72 - The customary law value of the Resolutions is that they are purportedly evidence of international support for a right to attack non-state actors on the territory of another state. Thus, they need only approve the action rather than authorise it. Action taken under art 51 requires only Security Council notification, not authorisation.
73 - See for example Dinstein, who goes as far as to say that the Resolutions “dispel all lingering doubts” about the scope of art 51, Yoram Dinstein War, Aggression and Self-Defence (4th ed, Cambridge University Press, Cambridge, 2005) at 207.
74 - Armed Activities, above n 18, Separate Opinion of Judge Simma, at .
75 - Vera Gowlland-Debbas “Functions of the United Nations Security Council in the International Legal System” in Michael Byers (ed) The Role of Law in International Politics: Essays in International Relations and International Law (Oxford University Press, Oxford, 2000) 285 at 300.
76 - Stefan Talmon “The Security Council as World Legislature” (2005) 99 AJIL 175 at 179.
77 - Myra Williamson Terrorism, War and International Law (Ashgate, Farnham, 2009) at 194.
78 - Christine Gray “The Use of Force and the International Legal Order” in Malcolm D Evans (ed) International Law (Oxford University Press, Oxford, 2010) 615 at 626, Thomas M Franck “Terrorism and the Right of Self-Defense” (2001) 95 AJIL 839 at 842.
79 - Williamson, above n 77, at 194.
80 - Lauri Hannikainen “The World After 11 September 2001: Is the prohibition on the use of force disintegrating?” in Petman and Klabbers, above n 21, at 452.
81 - Nico Schrijver “Responding to International Terrorism: Moving the Frontiers of International Law for ‘Enduring Freedom’?” (2001) 48 NILR 271 at 282.
82 - “Invocation of Article 5 Confirmed” (press release, 2 October 2001).\
83 - Statement by NATO Secretary-General Lord Robertson (press release, 8 October 2001).
84 - OAS Support for the Measures of Individual and Collective Self-Defence Established in OAS Res RC.24/RED, OEA/Ser.F/II.24 (1/01) (2001).
85 - Lindsay Moir Reappraising the Use of Force: International Law, Jus Ad Bellum and the War on Terror (Hart Publishing, Oxford, 2010) at 71.
86 - Statement by Russian Federation President V V Putin, Annex to Letter Dated 11 September 2002 from the Permanent Representative of the Russian Federation to the United Nations Addressed to the Secretary-General, UN Doc. S/2002/1012 (2002) at 2, quoted in Reinold, above n 69, at 253.
87 - Reinold, above n 69, at 257.
88 - Quoted in ibid.
89 - Victor Kattan “Israel, Hezbollah and the Conflict in Lebanon: An Act of Aggression or Self- Defense?” (2006) 14(1) Hum Rts Brief 26 at 26.\
90 - Tom Ruys “Crossing the Thin Blue Line: An Inquiry into Israel’s recourse to self-defense against Hezbollah” 43 (2007) Stan J Intl L 265 at 269.
91 - Ibid, at 284, noting Lebanon did not appear on the US list of State sponsors of terrorism.
92 - Kattan, above n 89, at 26 and see SC Res 1701, S/Res/1701 (2006).
93 - Quoted in Ruys, above n 90, at 270-271.
94 - Raphael Van Steenberghe “Self-Defence in Response to Attacks by Non-state Actors in the Light of Recent State Practice: A Step Forward?” (2010) 23 LJIL 183 at 193.
95 - Quoted in Ruys, above n 90, at 270-271.
96 - Van Steenberghe, above n 94, at 189.
97 - Christian J Tams “The Use of Force Against Terrorists” (2009) 20 EJIL 359 at 382.
98 - EU Presidency “Statement on the Military Action undertaken by Turkey in Iraqi Territory” (press release, 25 February 2008).
99 - Sean D Murphy “Protean Jus Ad Bellum” (2009) 27 Berkeley J Intl Law 22 at 24-25.
100 - Van Steenberghe, above n 94, at 194.
101 - “Si Quito hubiera cooperado, la incursión se abría evitado: Juan Manuel Santos” reproduced in Kintto Lucas, “Crisis sin solución a la vista” (“Crisis without a solution in sight”) (3 March 2008) http://www.ipsnoticias.net/nota.asp?idnews=87646.
102 - See Reinold, above n 69, at 274.
103 - OAS Res, CP/Res 930 (1632/08) (2008).
104 - Ibid.
105 - Reinold, above n 69, at 274.
106 - Laurie R Blank and Benjamin R Farley “Characterizing US Operations in Pakistan: Is the United States Engaged in an Armed Conflict?” (2010) 34 Fordham Intl LJ 151 at 183.
107 - Mary Ellen O’Connell “Unlawful Killing with Combat Drones: A Case Study of Pakistan, 2004-2009” (2010) Notre Dame Law School Legal Studies Research Paper No 09-43.
108 - Murphy, above n 33, at 10.
109 - Ashley S Deeks “Pakistan’s Sovereignty and the Killing of Osama bin Laden” (2011) 15 ASIL Insights Issue 11 at 3.
110 - Unfortunately, no examples of state practice are given. The reader is referred to Deeks “‘Unwilling or Unable’: Toward a Normative Framework for Extra-Territorial Self-Defense”  VirgJlIntLaw 6; (2011-2012) 52 Va J Intl L 483.
111 - Deeks, above n 109, at 3.
112 - Ibid.
113 - Jordan J Paust “Self-Defence targeting of non-state actors and the permissibility of US use of Drones in Pakistan  19 J Transnatl L & Poly 237 at 250.
114 - Deeks, above n 109, at 4.
115 Green, above n 19, at 47.
116 - Tams, above n 97, at 382.
117 - Murphy, above n 33, at 36.
118 - Ruys, above n 90, at 281.
119 - Negroponte, above n 70.
120 - Murphy, above n 99, at 23.
121 - Matthew C Waxman “The Structure of Terrorism Threats and the Laws of War” (2010) 20 Duke J Comp & Intl L 429 at 443.
122 - Famously, art 59 of the Statue of the International Court of Justice provides that the decisions of the Court have no binding force except between the parties and in respect of that particular case. While there is no doctrine of precedent as such, the Court avoids self-contradiction; in Land and Maritime Boundary between Cameroon and Nigeria (Preliminary Objections)  ICJ Rep 275 at  the Court held that “[t]he real question is whether, in this case, there is cause not to follow the reasoning and conclusions of the earlier cases.” A development in customary international law could provide such a reason.
123 - Barbour and Salzman, above n 34, at 84.
124 - Ibid, at 97.\
125 - Ruys, above n 90, at 286.
126 - These same qualifications appeared in the subsequent SC Res 1851, S/Res/1851 (2008), authorising the use of “all necessary measures” to suppress piracy.
127 - Kimberley N Trapp “Necessity, Proportionality, and the Right of Self-Defence against Non- state Terrorist Actors” (2007) 56 ICLQ 141 at 145.
128 - Ibid, at 147. Van Steenberghe also makes this point, above n 94, at 202.
129 - Trapp, above n 127, at 150.
130 - Green, above n 19, at 48.
131 - Paust, above n 113, at 256.
132 - See page 13.
133 - Trapp, above n 127, at 146.
134 - Ibid, 150.
135 - Tadić, above n 44, at 117.
136 - Barbour and Salzman, above n 34, at 74.
137 - Michael J Glennon “The Fog of Law: Self-Defense, Inherence, and Incoherence in Article 51 of the United Nations Charter” (2002) 25 Harv J L & Pub Poly 539 at 543.
138 - Tams, above n 97, at 385.
139 - Ibid, at 392.
140 - Van Steenberghe, above n 94, at 194.
141 - Antonio Cassese “The Nicaragua and Tadić Tests Revisited in light of the ICJ Judgment on Genocide in Bosnia” (2007) 18 EJIL 649 at 653.
142 - Ibid, at 654.
143 - Cassese sat as a judge in this case.
144 - Tadić, above n 44, at 131.
145 - Ibid, at 137.
146 - Cassese, above n 141, at 666.
147 - Nicaragua, above n 7, at .
148 - Ruys, above n 90, at 293.
149 - Kimberley N Trapp “The Use of Force against Terrorists: A Reply to Christian J Tams” (2010) 20 EJIL 1049 at 1053.
150 - Glennon, above n 137, at 550.
151 - Paust, above n 113, at 252.
152 - Constantine Antonopoulous “Force by Armed Groups as Armed Attack and the Broadening of Self-Defence” (2008) NILR 159 at 161.
153 - Schrijver, above n 81, at 286.
154 - Mary Ellen O’Connell “Limiting Self-Defense to Preserve the Peace and Protect Human Rights” (Wallenberg Symposium 2007, Osgoode Hall Law School, 17 January 2007) at 3.
155 - Kammerhofer, above n 62, at 113.
156 - Ruys, above n 90, at 282.
157 - Schrijver, above n 81, at 289.
158 - Tams, above n 97, at 394.
159 - Deeks, above n 109, at 4.
160 - Ruys, above n 90, at 294.
161 - Jules Lobel “The Use of Force to Respond to Terrorist Attacks: The Bombing of Sudan and Afghanistan” (1999) 24 Yale J Intl L 537 at 543.
162 - Mary Ellen O’Connell “Preserving the Peace: The Continuing Ban on War between States” (2007-2008) 38 Cal W Intl LJ 41 at 48.
163 - Franck, above n 78, at 843.
164 - Antonopoulous, above n 152, at 166.
165 - Reinold, above n 69, at 246.
166 - Franck, above n 6, at 816.
167 - Armed Activities, above n 18, at .
168 - Tams, above n 97, at 376. SC Res 1273, S/Res/1273 (2001) is an example of such.
169 - Wall Opinion, above n 24, Separate Opinion of Judge Kooijmans at .
170 - Paust, above n 113, at 258.
171 - Antonopoulous, above n 152, at 170.
172 - Waxman, above n 121, at 440.
173 - Ibid, at 444.
174 - Tams, above n 97, at 372.
175 - Kammerhofer, above n 62, at 113.
176 - Thomas M Franck “The Power of Legitimacy and the Legitimacy of Power: International Law in an Age of Power Disequilibrium” (2006) 100 AJIL 88 at 89.
177 - Independent International Commission on Kosovo “The Kosovo Report: Conflict, International Response, Lessons Learned” (Oxford, Oxford University Press, 2000) at 4.
178 - Martti Koskenniemi “‘The Lady Doth Protest too Much’ Kosovo, and the turn to Ethics in International Law” (2002) 65 MLR 159 at 171.
179 - Bruno Simma “NATO, the UN and the use of force: legal aspects” (1999) 10 EJIL 1 at 22.
180 - Anthea Roberts “Legality versus Legitimacy: can uses of force be illegal but justified?” in Philip Alston and Euan McDonald (eds) Human Rights, Intervention and the Use of Force (Oxford, Oxford University Press, 2008) 177 at 188.
181 - Simma, above n 179, at 22.
182 - Hilary Charlesworth “International Law: A Discipline of Crisis” (2002) 65 MLR 377 at 391.
183 - Kenneth Anderson “Targeted Killing in US Counterterrorism Strategy and Law” (Working Paper of the Series on Counterterrorism and American Statutory Law, 2009) at 21.
184 - Ibid.
185 - Nicholas Rostow “International Law and the Use of Force: A Plea for Realism” 34 (2009) Yale J Intl L 549 at 557.
186 - Gregory E Maggs “The Campaign to Restrict the Right to Respond to Terrorist Attacks in Self-Defense under the UN Charter and what the United States can do about it” (2006) 4 Regent J Intl L 149 at 169.
187 - Reinold, above n 69, at 248.
188 - Koskenniemi, above n 178, at 174.
189 - Murphy, above n 99, at 40.
190 - Rosalyn Higgins Themes and Theories: Selected Essays, Speeches and Writings in International Law (Oxford University Press, Oxford, 2009) at 1123.
191 - Cassese, above n 141, at 668.
192 - Higgins, above n 190, at 1123.
193 - Thomas M Franck Judging the World Court (Priority Press Publications, New York, 1986) at 55.
194 - Franck, above n 6, at 817.
195 - Glennon, above n 137, at 540.
196 - Koskenniemi, above 178, at 172.
197 - Koh, above n 1.