Rothwell, Donald R --- "Anticipatory Self-Defence in the Age of International Terrorism Special Edition: The United Nations and International Legal Order" [2005] UQLawJl 23; (2005) 24(2) University of Queensland Law Journal 337

ANTICIPATORY SELF-DEFENCE IN THE AGE OF INTERNATIONAL TERRORISM

DONALD R ROTHWELL ^[∗]

I. Introduction

The use of force by one State against another is one of the most significant foreign policy decisions that any State can make. It is also an action heavily constrained by international law and which carries with it considerable international legal consequences. Following the two World Wars of the Twentieth Century, the international community sought to construct a new world order framed around the 1945 United Nations Charter.^[1] The Charter seeks to regulate a number of fundamental aspects of international relations including the maintenance of international peace and security, recognition of the equality of states, respect for human rights, and limitations upon the use of force. Article 2(4) of the Charter places limitations on the use of force by States in the everyday conduct of their international relations, without however going so far as to prohibit States maintaining standing armies for purely defensive purposes. In times of fracture or schism in the international system, the Charter confers certain powers upon the UN Security Council to restore international peace and security including, if necessary, the capacity to authorise the use of force. This ‘theoretical’ power of the Security Council is one which following the end of the Cold War and commencing with the 1990-1991 Gulf War has been more frequently exercised. However, the overwhelmingly most common use of force in the conduct of relations between States has since 1945 been founded on self-defence.

The right of self-defence has a long-standing history in international relations and international law and continues to be recognised under Article 51 of the United Nations Charter. Article 51 relevantly provides:

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.

Debate remains over whether Article 51 is an exhaustive statement on the right of self-defence, or whether an independent customary international law right of self-defence still exists. There has been no conclusive resolution of this issue and certainly the inclusion of the word ‘inherent’ in Article 51 suggests that the right of self-defence was one which pre-existed the Charter.

Self-defence is a principle however which has a number of manifestations. Classical self-defence can be characterised as arising when one State launches an unprovoked attack against another, such that the State suffering the attack seeks to respond by the use of armed force in order to repel, quell or quash the aggressor State.^[2] Under the UN Charter, individual self-defence has been expanded to extend to ‘Collective Self-Defence’ whereby the State suffering an initial armed attack may respond collectively in concert with like-minded States.^[3] Both individual and collective self-defence have a firm foundation in both customary international law and the UN Charter, notwithstanding that certain aspects of individual military operations undertaken in purported reliance upon self-defence may be controversial. The same cannot be said for ‘anticipatory self-defence’ undertaken either individually or collectively.

Anticipatory self-defence (ASD) builds upon the principle of classical self-defence to by extension assert a right whereby a State which believes it is about to suffer an armed attack retains the right to launch a defensive military strike upon an expected aggressor State in order to thwart an armed attack it may have been on the brink of suffering. Most importantly the doctrine does not rely upon a State suffering the consequences of an actual armed attack before it can seek to defend itself from further attack but that rather the State ‘anticipates’ the attack and acts in such a manner as to defuse the threat posed by the ‘aggressor’ State. The doctrine is controversial, as at face value it runs counter to the UN Charter not only because there is no express reference to ‘anticipatory self-defence’ in Article 51, but also because the first use of allegedly ‘defensive’ military force runs the risk of being characterised as a breach of Article 2(4). Nonetheless there has been continuing debate over the legitimacy of ASD since the adoption of the UN Charter, with various cases of state practice contributing to that debate.

The debate over ASD has gained greater momentum following the events of September 2001. In particular, the focus has been on whether States have a capacity to launch anticipatory military strikes against terrorist bases, training facilities, or camps that are engaged in preparations for an armed attack against a State or State interests. To that end, the 2002 US National Security Strategy articulated a so-called doctrine of ‘preemption’ advocating the ‘preemptive use of force’ against known terrorist threats.^[4] Debate over the legitimacy of such a doctrine became entangled at the time in wider debates over the use of military force against Iraq arising from concerns over that country’s assumed possession of weapons of mass destruction (WMD). Purported linkages between Iraq and certain terrorist organizations and concerns over Iraq’s capacity to supply or transfer terrorist organizations with WMD further fuelled debate over whether preemptive force against Iraq could be justified, or whether a case for ASD could be made out.

Ultimately, a variety of legal justifications were put forward for the use of force against Iraq in March 2003 by the US, United Kingdom and Australia.^[5] However, the debates which took place in 2001-2003 created a need for further definition to be given to the right of self-defence in international law and in particular a reassessment of ASD and its relationship, if any, with the doctrine of preemption. This article seeks to explore these issues by way of a reassessment of the principle of self-defence, the legitimacy if any of ASD, and then a reflection upon the events following September 2001 and the debates leading up to the 2003 Iraq War. An analysis will also be undertaken of recent initiatives for reform of the UN system, in particular the use of force, before conclusions are reached as to the status of ASD in contemporary international law.

II. Self-Defence and International Law

The classic statement of self-defence arose following the Caroline incident in 1837.^[6] Here the British seized the Caroline which had been used by American rebels for armed raids on Canadian territory. The ship was set on fire and sent over Niagara Falls, resulting in the death of two US nationals. In the resulting diplomatic correspondence between the US and Great Britain regarding the legitimacy of the British action, it was asserted by the US Secretary of State, Daniel Webster, that Britain would need to show ‘a necessity of self-defence, instant, overwhelming, leaving no choice of means, and no moment for deliberation’.^[7] This element is identified as that of ‘necessity’, in that the State exercising the right of self-defence has acted in response to an armed attack thereby necessitating a response in order to defend itself from further attack.

The additional element in the exercise of the right of self-defence is that of proportionality. In the Caroline it was described as:

It will be for it [Great Britain] to show, also, that the local authorities of Canada, even supposing the necessity of the moment … did nothing unreasonable or excessive; since the act justified by the necessity of self-defence, must be limited by that necessity and kept clearly within it.^[8]

The ‘right’ of self-defence is therefore one which must be exercised with restraint and it does not confer upon the responding State a capacity to launch a military response which far exceeds the threat posed by the original attack that it suffered.

The Caroline test is one which has survived for nearly two centuries including the recognition of the right of self-defence in the UN Charter. The incident is of considerable interest given some of the parallels the facts raise to contemporary events, and that it was an incident involving the US.^[9] Sir Robert Jennings has described the Caroline test as the ‘locus classicus of the law of self-defence’,^[10] noting that despite the case turning on its facts, ‘both parties were agreed as to the law makes it all the more valuable as a precedent.’^[11] The Caroline test was adopted by the International Military Tribunal in Nuremberg,^[12] and as noted by Dinstein, whilst it has been argued that it has not survived the adoption of the UN Charter, ‘there is no corroboration of this view in the text … ’.^[13]

During the Charter era, the Caroline test of necessity and proportionality has from time to time been considered and assessed by the International Court of Justice (ICJ). Often, those decisions have not proven to be particularly decisive, with the exception of the Nicaragua Case (Merits).^[14] In a wide ranging review, the ICJ noted the existence of the right of both individual and collective self-defence in customary international law.^[15] Importantly for present purposes, the Court stressed that ‘[i]n the case of individual self-defence, the exercise of this right is subject to the State concerned having been the victim of an armed attack.’^[16] In considering what constitutes an ‘armed attack’ the Court was prepared to extend it to not only action by regular military forces across an international border, but also the sending by a State across a border of ‘armed bands, groups, irregulars or mercenaries’^[17], provided that the attack is of sufficient gravity.^[18]

The inherent right of both individual and collective self-defence was reaffirmed by the United Nations Security Council in Resolution 1368 (12 September 2001)^[19] and Resolution 1373 (28 September 2001),^[20] adopted following the 11 September 2001 terrorist attacks on the United States. Consequently, the United States sought to rely upon the right of both individual and collective self-defence for its military operations in Afghanistan in 2001-2002. These actions by both the Security Council and the United States reflect an extended dimension to the right of self-defence in that the US had not suffered an attack by another State but rather by a terrorist organization with bases in and support from another State. Whilst a careful distinction needs to be made between notions of ‘State-sponsored terrorism’ and the precise relationship that existed between Afghanistan’s Taliban Government and Al Quada, ultimately there is no denying that the Taliban did not seek to cooperate with the US and the international community in addressing the ongoing threat posed by the Taliban, including arranging for their detention, arrest and prosecution for crimes they may have committed under Afghan law or international law.

Whether an armed attack is imputable to a foreign State becomes pivotal when seeking to exercise the right of self-defence, and this indeed was the case with Afghanistan in 2001. Whilst the ICJ has never been called upon to assess the legality of that military operation,^[21] comments that it made in the context of its 2004 Advisory Opinion on the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory are of note.^[22] An Advisory Opinion was sought from the Court by the United Nations General Assembly^[23] as to the legal consequences arising from the construction of a wall by Israel in the Occupied Palestinian Territory. In considering this question, the court principally assessed international humanitarian law, but also reviewed principles of self-defence. The Court restated the terms of Article 51 of the Charter and then went on to note:

Article 51 of the Charter thus recognizes the existence of an inherent right of self-defence in the case of an armed attack by one State against another State. However, Israel does not claim that the attacks against it are imputable to a foreign State. The Court also notes that Israel exercises control in the Occupied Palestinian Territory, and that, as Israel itself states, the threat which it regards as justifying the construction of the wall originates within, and not outside, that territory. The situation is thus different from that contemplated by Security Council resolutions 1368 (2001) and 1373 (2001), and therefore Israel could not in any event invoke those resolutions in support of its claim to be exercising a right of self-defence.^[24]

These observations lend weight to the view that armed external attacks originating from another State can be legitimately responded to on the grounds of self-defence.^[25]

In light of the actions of the United Nations Security Council following September 2001, subsequent pronouncements by the ICJ,^[26] and relevant state practice, it is clear that the right of self-defence continues to evolve, whether it be via the interpretation of Article 51 of the Charter or the principle as reflected in customary international law. The decision in the Nicaragua Case helpfully expanded the principle beyond engagement by regular armed forces. In addition, it is clear in light of both that decision and practice since 2001 that there is no need for a State or State entity to be directly responsible for the initial attack before a legitimate armed response can take place.^[27] The parameters of classical self-defence have therefore proved capable of expansion to meet changing threats and the needs of States in the international community to directly respond to those threats.

III. Anticipatory Self-Defence and International Law

In reviewing ASD a number of issues arise for consideration. The first is the existence, if at all, of the right prior to the adoption of the Charter. The second is whether following the adoption of the Charter and Article 51 any scope remains for such a principle.

A. Customary International Law Position

Prior to adoption of the Charter it was generally assumed that the right of anticipatory self-defence existed. Brownlie has noted that ‘customary law permitted anticipatory action in face of imminent danger. There can be little doubt that the right of self-preservation and the doctrine of necessity comprehended anticipatory action’.^[28] Support for this view was based upon the Caroline, the views of publicists,^[29] and examples from state practice.^[30] However, pre-1945 views of ASD must now be considered in light of the UN Charter and the intention of the framers of that instrument to create a new international order following the events of the first 45 years of the Twentieth Century. Therefore, the principal issue must now be whether pre-1945 state practice and customary international law survived the adoption of the Charter and the subsequent practice of the international community in the years which have followed.

Debate remains over whether Article 51 of the UN Charter, with its requirement for an ‘armed attack’, has now extinguished the right of ASD, or whether such an ‘inherent right’ still remains. Dinstein has argued that self-defence consistent with Article 51 envisages a resort to ‘counter-force’, and any exercise of force prior to the attack commencing or incurring injury or damage carries significant risks:

When a country feels menaced by the threat of an armed attack, all that it is free to do—in keeping with the Charter—is make the necessary military preparations for repulsing the hostile action should it materialize, as well as bring the matter forthwith to the attention of the Security Council. … Regardless of the shortcomings of the system, the option of a preemptive use of force is excluded by Article 51.^[31]

If a right of ASD was considered to exist, what form would it take? To begin it would seem that the right would need to meet the Caroline test of necessity and proportionality, albeit in a slightly varied context. Any purported exercise of the right of ASD would demand identification of clear hostile intent on the part of an aggressor State against which the imperilled state feels forced to act. Evidence is therefore the key in any exercise of this right. Brownlie has noted:

It is possible that in a very limited number of situations force might be a reaction proportionate to the danger where there is unequivocal evidence of an intention to launch a devastating attack almost immediately. However, in the great majority of cases to commit a state to an actual conflict when there is only circumstantial evidence of impending attack would be to act in a manner which disregarded the requirement of proportionality.^[32]

This suggests a high threshold not only in terms of the available intelligence going directly to such a potentially devastating strike and the capacity to deliver that strike, but also the actual intention to deliver such a strike. Throughout the Cold War there could have been little doubt of the capacity of the US or USSR to launch a devastating strike upon each other nor of their actual capacity to deliver such a nuclear strike, but making a judgment that such a strike was imminent would have required the possession of knowledge which it is doubtful any State could possess.

B. State practice and Anticipatory Self-Defence

There are two principal cases of the purported exercise of ASD in the UN era: the 1981 Israeli attack on Iraq, and the 1986 US attack on Libya. On 7 June 1981, Israel undertook an air strike on Osiraq in Iraq where a French-supplied nuclear reactor was under construction. The military intervention was undertaken by fourteen aircraft. All of the aircraft were able to avoid identification and returned to Israel safely. Israel sought to justify this action on the grounds of self-defence. Israel had for several years been concerned about the Iraqi program, and ultimately the potential of that program to produce nuclear weapons that would be used against Israel. As no armed attack against Israel had occurred in and around the time of the Osiraq bombing, the only legal foundation for Israel’s actions could be ASD. Evidence subsequently gathered by the international community clearly suggests that it was Iraq’s intention to use the Osiraq facility to build nuclear weapons, however it is estimated it would have taken between 12 to 18 months before that capacity had been finally reached. Iraq’s ultimate intention as to how it may have made use of a nuclear weapons capability remains a point of speculation.^[33]

The United Nations Security Council debated the Israeli action and unanimously adopted SC Resolution 487.^[34] That Resolution reaffirmed the application of Article 2(4) of the UN Charter, and expressed concerns ‘about the danger to international peace and security created by the premeditated Israeli air attack on Iraqi nuclear installations…’. The Resolution further provided that the Security Council:

1. Strongly condemns the military attack by Israel in clear violation by the Charter of the United Nations and the norms of international conduct;

2. Calls upon Israel to refrain in the future from any such acts or threats thereof… .

The Israeli attack on Osiraq has been the subject of considerable debate amongst international lawyers. Other than the United Nations Security Council debate condemning the action, there was no formal consideration of the legality of the action by a body such as the ICJ. McCormack has summed up the debate in the international law community as follows:

Some writers argue that anticipatory self-defence is no longer available under the terms of Article 51 and either dismiss the Israeli action as illegal on that basis or go on to justify the action in some other way. Other commentators argue that Article 51 preserves the right of anticipatory self-defence and then conclude either that Israel’s action did not come within the limits of that right or that the action was a justifiable exercise of that right.^[35]

Dinstein has subsequently argued that there was no need to consider anticipatory self-defence in this instance and that Israel’s actions were consistent with the ongoing state of war that existed between Iraq and Israel.^[36] Setting aside the legitimacy of that argument and whether even during a time of technical armed conflict a tactical strike of the type which took place at Osiraq is justified, Dinstein’s conclusion that the Israeli action was not supportable at law is compelling. He notes:

Had Israel been at peace with Iraq, the bombing of the site would have been prohibited, since (when examined in itself and out of context of an on-going war) it did not qualify as a legitimate act of self-defence consonant with Article 51. This is the position de lege lata … .^[37]

In the case of the US attack on Libya, on 15 April 1986, US aircraft bombed three targets in Tripoli and two sites near Benghazi, Libya. The US military action came ten days after a bomb exploded in a night club in Berlin frequented by US servicemen, resulting in three deaths and 200 injuries. It also followed years of tension between the US and Libya over alleged Libyan links to terrorist attacks on the US. The US sought to justify the action on the grounds of self-defence, including Article 51. In addition, it was also stated that the attacks were undertaken because there was ‘clear evidence that Libya is planning future attacks’^[38] and that the ‘pre-emptive action against his terrorist installations will not only diminish Colonel Qaddafi’s reign of terror—it will provide him with incentives to alter his criminal behaviour.’^[39] The debate which followed in the United Nations Security Council was inconclusive and split along political lines. No UNSC Resolution was adopted dealing with this armed attack, nor was there any consideration of this action by the ICJ.

The weight that can be assigned this instance of ASD is somewhat clouded due to the state of ongoing tension that had existed between Libya and the US, and the clear link between the US bombing and the Berlin nightclub bomb of a few days earlier.^[40] Nevertheless, there was a clear element in the US action of seeking to deter Libya from launching a military strike against the US or its interests abroad.

In neither of the two cases referred to above was there a conclusive determination of the legality of the actions taken. While UNSC Resolution 487 condemned Israel’s 1981 bombing of Iraq it made no judgment on whether the right of ASD was recognised under international law, or whether if it was recognised that Israel had failed to make out a case for its application. In the case of the US attack on Libya, there was no conclusive Security Council debate and US justification for the action was also partly grounded on self-defence in response to Libyan-sponsored terrorist attacks.

In addition to the inconclusive state practice, judicial analysis by the ICJ has also been inconclusive. The Court has not had occasion to consider the legitimacy of ASD principally because the issue has not arisen in any contentious cases.^[41] Likewise, in the two Advisory Opinions delivered by the Court which sought to review aspects of the legitimate use of force, the ICJ did not express any views on the legitimacy of ASD.^[42] In light then of the relevant state practice and judicial pronouncements on the matter, any clear appreciation of the status of ASD must rest with an interpretation of the UN Charter.

IV. The Debates following the 2001 Terrorist Attacks on the US

The 2001 terrorist attacks upon the US were a defining world event which had considerable ramifications for international law.^[43] Two principal issues arose following September 11. First, how could the terrorist attacks and the subsequent responses to those attacks led by the US and its allies be characterised under international law? Second, was existing international law adequate to deal with the threats posed by terrorist organizations like Al-Quada or was there a need for new responses? The first of these questions has already been partly answered in the context of the Security Council response of September 2001 and the implications of that response for self-defence.^[44]

As to the second question, the capacity of international law to cope with the new post September 11 security environment was principally reflected in the concerns articulated by States grappling to respond to new scenarios. Whilst US concerns were understandable, other governments also expressed doubts as to whether the international legal system was capable of satisfactorily responding. For example, the Australian Minister for Defence, Senator Robert Hill, in the wake of both the September 11 terrorist attacks and the Bali bombings of 12 October 2002, noted with respect to the Caroline principles of self-defence:

How should these principles be interpreted in the age of over-the-horizon weaponry, computer network attack and asymmetric threats when warning times are reduced virtually to zero and enemies can strike almost anywhere? The world in which the UN Charter was drafted was very different, with the preoccupation being to prevent the massive conventional wars between States that disfigured the first half of the twentieth century.^[45]

In addition to debating whether the UN Charter was adequate to deal with the new security threats, there was also debate over whether new doctrines in support of the use of force were required. The principal document which has led debate on this question was The National Security Strategy of the United States of America released by President Bush in September 2002. In the President’s Foreword, a concise assessment is given of the security challenges faced by the United States following the events of 2001. Making clear that the US will seek to act against emerging threats by working cooperatively to preserve the peace with other members of the international community, the President asserts that ‘as a matter of common sense and self-defense, America will act against such emerging threats before they are fully formed.’^[46] The National Security Strategy goes on to identify the threats posed by weapons of mass destruction in the hands of so-called ‘rogue states’ and terrorists and makes clear that the threats posed by such entities must be stopped.^[47] Arguing that a ‘reactive posture’ is no longer suitable in dealing with these threats, the Strategy concludes:

We must adapt the concept of imminent threat to the capabilities and objectives of today’s adversaries. Rogue states and terrorists do not seek to attack us using conventional means. … they rely on acts of terror and, potentially, the use of weapons of mass destruction …



The United States has long maintained the option of preemptive actions to counter a sufficient threat to our national security. The greater the threat, the greater the risk of inaction—and the more compelling the case for taking anticipatory action to defend ourselves, even if uncertainty remains as to the time and place of the enemy’s attack. To forestall or prevent such hostile acts by our adversaries, the United States will, if necessary, act preemptively.^[48]

The National Security Strategy articulated the US position on the use of force against looming State or non-State threats in the wake of September 11. However, the legal justification was principally based upon ASD,^[49] and no attempt was made to distinguish between any variant of self-defence whether it be classical, anticipatory, or preemptive.^[50]

Some of the official US thinking justifying the legality of ‘preemption’ can be found in the published views of the Legal Adviser to the Department of State, William H Taft IV. In November 2002, he wrote of the US position on self-defence within the parameters of the Charter and customary international law as follows: ‘The United States has long held that … a state may use force in self-defense: 1. if it has been attacked, or 2. if an armed attack is legitimately deemed to be imminent.’^[51] Taft goes on to review relevant state practice, including the 1981 Israeli strike on Osiraq and the Security Council’s response, and also the contemporary relevance of the Caroline. After noting the content of the diplomatic exchanges between the British Foreign Minister and US Secretary of State he observes:

Neither Webster nor Ashburton disagreed about the existence of an inherent right to use force in self-defense, but rather on its application to the set of facts before them. In fact, Secretary Webster pointed out, ‘the extent of this right is a question to be judged by the circumstances of each particular case.’ The difficulty lies in determining, as Lord Ashburton asked, ‘when begins your right to self-defend.’^[52]

In more recent comments made to the American Society of International Law in 2004, Taft articulates the US position that ‘[i]n the traditional framework of self-defense, preemptive use of force is justified only out of necessity, which requires both a credible, imminent threat and the exhaustion of peaceful remedies.’^[53] Noting, however the changed international security environment arising from WMDs, the intentions of those who possess such weapons, and the consequences arising from the use of such weapons, Taft goes on to argue that:

The doctrine of preemption to prevent a catastrophe resulting from an attack by weapons of mass destruction is, however, a natural extension of—and fully consistent with—the traditional right of individual self-defense to ensure that the right of self defense attaches early enough to be meaningful and effective.^[54]

What became clear in the wake of the 2001 terrorist attacks upon the United States was that whilst classical self-defence was the principal ground legitimating the armed attack upon Afghanistan by the United States and its allies, the ground was being laid for the development of a new doctrine of ‘preemption’ which clearly went beyond classical self-defence. The distinction between preemption and ASD, however, was unclear, other than an assertion that threats to individual and global security had radically altered with the rise of rogue States possessed of WMD capability and their connection with international terrorist organizations.

V. The Debates Prior to the 2003 Military Intervention in Iraq

In the period immediately prior to the commencement of ‘Operation Iraqi Freedom’ by the United States and its coalition partners in March 2003 there was considerable debate as to the legitimacy of military action against Iraq. Given the views put forward by the US in its September 2002 National Security Strategy of rogue States possessing WMD and their links with terrorist organizations, it was clear that the US was preparing the ground for military intervention in Iraq. Additional legal arguments were also being considered, including humanitarian intervention, reliance upon existing Security Council Resolutions, and ASD. The exercise of ASD in the case of Iraq was particularly focussed on two aspects:

• That Iraq had not fully disarmed itself of WMD in conformity with UN Security Council Resolution 687 (1991) adopted following the 1991 Gulf War and possessed the capacity and intent to launch a strike against neighbouring States or the interests of foreign States.

• That Iraq had shown sympathy to international terrorist organizations, in particular Al-Quada, and was in the position to give those organizations WMD capacity with potentially catastrophic consequences for western States such as the US.

The linkage between Iraq and the uncertainty over whether it had fully disarmed itself of WMD in compliance with UN Resolutions was further heightened by the stop-start weapons inspection regime which had been deployed in Iraq since 1991 thereby giving no confidence to some members of the international community, especially the US, that Iraq no longer had a WMD capacity. Notwithstanding the renewed mandate given to the International Atomic Energy Authority (IAEA) and UNMOVIC inspectors to conduct further Iraqi weapons inspections,^[55] there was scepticism amongst some in the international community that these mechanisms would prove fruitful.

The case of Iraq posed new and novel issues for the debate over WMD. There had to that time been no instance where ASD had been relied upon in response to a state providing WMD to terrorist organisations. The debate brought together elements which existed in both the Israeli bombing of Osiraq in 1981 and the US bombing of Libya in 1986: nuclear weapons and state-sponsored or state-supported terrorists. However it also posed the question as to whether ASD could be exercised collectively and whether coalitions of States could join together in anticipation of an armed attack against one of them and launch a military strike against the aggressor State or a State actively engaged in assisting non-State actors such as terrorists preparing to launch an armed attack.

Ultimately, there was little reliance placed upon ASD as a justification for ‘Operation Iraqi Freedom’ when it was eventually commenced by the US and its allies in late March 2003. Whilst the US has never released any official documentation setting out the legal basis for the Iraq campaign, the writings of the US State Department Legal Advisor make it clear that preemption was the foundation for the military action.^[56] For Australia and Britain,^[57] principal reliance was placed upon authorisation founded in existing Security Council Resolutions commencing with those adopted immediately following the Iraqi invasion of Kuwait in 1990,^[58] following the Gulf War cease-fire in 1991,^[59] and in 2002 when the Council gave Iraq one final chance to comply with its disarmament obligations.^[60] Whilst all of these legal arguments in support of the 2003 Iraqi intervention have been subject to wide ranging critique,^[61] neither the arguments in support of the Iraq war or those against have necessarily advanced the argument as to ASD any further.

VI. Reform of the UN Charter and Expanded notions of Self-Defence

In the wake of ‘Operation Iraqi Freedom’ there has been considerable analysis and assessment of the future of the UN system. In addition to the ongoing debates about reform of the Security Council and its membership, there has also been consideration as to whether the UN is capable of addressing the threats to global security posed by international terrorism. This debate has been driven not only by the division within the Security Council in the months immediately preceding the 2003 Iraq intervention, but also by the ability of the Council and the UN as a whole to respond to threats posed by non-State actors given the organisation’s State-centric bias.

Recognising these challenges and the need for the UN to respond, in 2003 the Secretary-General, Kofi Annan commissioned a High-level Panel to consider challenges to international security in the wake of the events of September 2003 but also international humanitarian crises. The report of the Panel, A more secure world: Our shared responsibility, released in late 2004, made a series of recommendations for UN reform in addressing new international security challenges.^[62] In addition to the promotion of a ‘responsibility to protect’ peoples facing severe humanitarian crises, the report also reviewed the challenges of addressing the proliferation of WMD and the threats posed by international terrorism. The High-Level Panel concluded:

The norms governing the use of force by non-State actors have not kept pace with those pertaining to States. This is not so much a legal question as a political one. … The United Nations must achieve the same degree of normative strength concerning non-State use of force as it has concerning State use of force.^[63]

In March 2005 the Secretary-General followed up the High-Level Panel report with his own document addressing UN reform and challenges to international security. Entitled In larger freedom:Toward, development, security and human rights for all, this report reviews and endorses many of the recommendations made by the High-Level Panel. It directly addresses whether Article 51 of the Charter is adequate to deal with the new security environment noting that States have been divided over the question of preemption and states:

[T]his issue has deeply divided Member States. They have disagreed about whether States have the right to use military force pre-emptively, to defend themselves against imminent threats; whether they have the right to use it preventively to defend themselves against latent or non-imminent threats; and whether they have the right—or perhaps the obligation—to use it protectively to rescue citizens of other States from genocide or comparable crimes.^[64]

The Secretary-General concludes however that:

Imminent threats are fully covered by Article 51, which safeguards the inherent right of sovereign States to defend themselves against armed attack. Lawyers have long recognized that this covers imminent attack as well as one that has already happened.^[65]

This view is a strong endorsement of ASD, and whilst the Secretary-General’s report went on to recommend adoption of a new Security Council Resolution which would provide a set of effective guidelines on when and how use of force should be authorised,^[66] it was not seen as necessary to place limits around the use of force against imminent attack.

As part of the UN reform agenda, in September 2005 a World Summit was held in New York attended by many of the world’s leaders. Debate focussed on the issues raised by In larger freedom and the security issues considered by the 2004 High-Level Panel report. Ultimately on many fronts the 2005 World Summit Outcome document has been subject to criticism for its failure to engage with some of the underlying root causes of concern in the UN system such as the operations and membership of the Security Council and General Assembly, and the UN bureaucracy. However in the context of international security and the use of force, the World Summit Outcome reasserts the importance of international law and an effective multilateral system in addressing peace and security.^[67] In considering the use of force under the Charter, the Member States ‘reaffirm that the relevant provisions of the Charter are sufficient to address the full range of threats to international peace and security.’^[68] With respect to terrorism, ‘international cooperation to fight terrorism must be conducted in conformity with international law’,^[69] however no new legal initiatives are proposed to respond to international terrorism other than the finalisation and entry into force of treaties currently under negotiation. The only other significant reference to the use of force made in the World Summit Outcome is to the responsibility to protect from genocide, war crimes, ethnic cleansing and crimes against humanity.^[70]

VII. Concluding Remarks

A review of the international law dealing with self defence clearly shows that the doctrine is not only one of long standing but also flexibility. Ultimately, the debate which arose following the Caroline incident was not over the content of the doctrine but rather whether the circumstances relied upon by Great Britain justified the ship’s seizure and its subsequent loss. The circumstances of that case can themselves be seen as one in which military action was taken by Britain in the face of an anticipated attack.^[71] However, whilst the Caroline and incidents which followed confirm the clear existence of a right of self-defence and a form of ASD in customary international law prior to 1945, whether such a right remained intact following the adoption of the Charter remains debateable.

Some commentators such as Zoller have persuasively argued that in the wake of the Nicaragua case ‘preventive self-defense, as it was recognized under customary international law “for centuries” is a relic of the past’.^[72] However, the debates over whether the customary international law position has or has not survived the adoption of Article 51 only go to the issue of the contemporary foundation of ASD. Even if the customary position does not remain, there are also strong arguments that grounds for ASD can be found in the independent right of self-defence recognised in Article 51.^[73]

Here, weight has increasingly been given to the argument that the UN Charter is not a ‘suicide pact’. In the context of the threat posed by nuclear weapons, Higgins (now a Judge of the International Court of Justice), has noted:

… in a nuclear age, common sense cannot require one to interpret an ambiguous provision in a text in a way that requires a state passively to accept its fate before it can defend itself. And, even in the face of conventional warfare, this would seem the only realistic interpretation of the contemporary right of self-defence. It is the potentially devastating consequences of prohibiting self-defence unless an armed attack has already occurred that leads one to prefer this interpretation ... .^[74]

In the contemporary context which mixes WMD and international terrorism, Zoller has argued in reliance upon aspects of the National Security Strategy that ‘it is indeed both ‘manifestly absurd [and] unreasonable’ to compel States to wait like sitting ducks for the ‘wanton destruction and the targeting of innocents [by] rogue states and terrorists’.^[75] These seem to be the views that have been endorsed even by Kofi Annan with his concession that imminent threats are covered by Article 51 thereby permitting a right of States to defend themselves against imminent attack.^[76]

Ultimately then, the debate over ASD comes down to not its existence, but its content. Here the most important issue that will need to be addressed is the imminence of the expected attack. Questions such as the quality and level of the intelligence as to the nature of the attack, the imminence of the attack, the potential and capacity of the attack to cause significant harm and damage, and whether all diplomatic and peaceful means have been fully utilised to diffuse the potential attack become relevant. Ultimately, each instance of ASD must be judged on a case-by-case basis. For example, whilst the 1941 Japanese attack on Pearl Harbour is often used in support of the argument in favouring ASD by the US if it had been aware of the impending attack, Dinstein rightly characterises such an instance as being ‘interceptive self-defence’ as the attack upon Pearl Harbour would have been intercepted prior to its commencement.^[77] In the case of the 1981 Israeli attack upon Osiraq a good deal of the debate rested not upon the content of the right of ASD but whether Israel’s actions were premature under the circumstances. It would also seem clear that whilst ‘preemption’ is a doctrine which has grown from ASD, it remains distinctive in that whilst is it is founded on a notion of imminence of armed attack, the imminence of the attack is one-step further removed from that which traditionally has been required in support of ASD.

It is concluded then that the better view with respect to ASD is that it may be justified consistent with Article 51 and other provisions of the United Nations Charter such as the obligations in Chapters VI and VII, and customary international law if:

• The State which seeks to rely upon the doctrine has sought to use international mechanisms, through both the United Nations, and other international organizations including relevant regional organizations, to peacefully settle the dispute.

• The State which seeks to rely upon the doctrine has exhausted all available and practical legal means to settle the dispute.

• The State is responding to an overwhelming and clear threat and intention to use force by another State, an agent of the State, or from terrorists sponsored or supported by the State.

• The State when seeking to exercise the right adheres to the principles of necessity and proportionality and other relevant provisions of international law, including international humanitarian law.

• The State exercising the right immediately reports the matter to the United Nations Security Council for its further action.

A final element should be that any State which asserts and exercises a right of ASD should not only make itself politically accountable to the international community for its actions, but should also be prepared to have it actions scrutinized by the International Court of Justice.

The use of force in contemporary international relations is one of the most significant acts any State can undertake. Responding to an actual armed attack in self-defence whereby the State seeks to protect its very existence is one of the most fundamental values of statehood that can be exercised. The consequences however of launching anticipatory action and making an error of judgment that a presumed threat is not as great as anticipated is one which all States must bear the highest levels of accountability and state responsibility for.

^[∗] BA, LLB (Hons) (Qld); LLM (Alberta); MA (Calgary); PhD (Sydney); Challis Professor of International Law, Faculty of Law, University of Sydney.

^[1] Charter of the United Nations.

^[2] Britain’s response in 1982 to the Argentinian invasion of the Falkland Islands is often cited as a contemporary example of classical self-defence, see K R Simmonds, ‘The struggle for the Falkland Islands’ (1983) 32 International and Comparative Law Quarterly 262; F Hassan, ‘The sovereignty dispute over the Falkland Islands’ (1982) 23 Virginia Journal of International Law 53.

^[3] SC Res 1368 (12 September 2001) and 1373 (28 September 2001) adopted in the immediate aftermath of the terrorist attacks on the United States of American recognised the right of both individual and collective self-defence to respond to those attacks, and the US-led Coalition military response which followed in Afghanistan in October 2001 is an illustration of the exercise of collective self-defence. SC Res 1368, UN SCOR, 56th sess, 4370^th mtg, UN Doc S/RES/1368 (2001); SC Res 1373, UN SCOR, 56th sess, 4385^th mtg, UN Doc S/RES/1373 (2001).

^[4] President of the United States of America, National Security Strategy of the United States of America (2002), 15 (see discussion infra).

^[5] See discussion below.

^[6] For the facts, see the discussion in R Y Jennings. ‘The Caroline and McLeod Cases’ (1938) 32 American Journal of International Law 82, 82-84.

^[7] Britain, Parliamentary Papers Vol LXI (1843); Britain, British and Foreign State Papers Vol 30, 193.

^[8] Ibid.

^[9] Jennings notes that the diplomatic exchange between the US and Great Britain resulted in an acceptance of an apology by the US for the territorial infringement by British forces and ‘agreement of the two governments on the importance of the principle of non-intervention and the narrow limits of the exceptions’ (those being the exceptions noted above respecting self-defence); Jennings, above n 6, 91.

^[10] Jennings, above n 6, 92.

^[11] Jennings, above n 6, 92.

^[12] Nuremberg Trial (Judgment) (1946) 1 International Military Tribunal 171, 207.

^[13] Yorram Dinstein, War Aggression and Self-Defence (3^rd ed, 2001) 219.

^[14] Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America) (Merits) [1986] ICJ Rep 14 (‘Nicaragua Case’).

^[15] Ibid [193].

^[16] Ibid [195].

^[17] These terms were directly taken by the Court from Resolution on the Definition of Aggression, GA 3314 (XXIX), UN GAOR Supp (No 31), 29^th sess, 2319^th plen mtg, art 3(g), UN Doc A/RES/3314 (1974).

^[18] Nicaragua Case, above n 14, [195].

^[19] SC Res 1368 provided in its third operative paragraph ‘Recognizing the inherent right of individual or collective self-defence in accordance with the Charter’. SC Res 1368, UN SCOR, 56th sess, 4370^th mtg, UN Doc S/RES/1368 (2001).

^[20] SC Res 1373 provided in its fourth operative paragraph ‘Reaffirming the inherent right of individual or collective self-defence as recognized by the Charter of the United Nations as reiterated in resolution 1368 (2001).’ SC Res 1373, UN SCOR, 56th sess, 4385^th mtg, UN Doc S/RES/1373 (2001).

^[21] There has been considerable academic comment on this question, see for example Gilbert Guillaume, ‘Terrorism and International Law’ (2004) 53 International and Comparative Law Quarterly 537, 546; George K Walker, ‘The Lawfulness Of Operation Enduring Freedom’s Self-Defense Responses’ (2003) 37 Valparasio University Law Review 489, 521-532 ; Jordan J Paust ‘Use of Armed Force against Terrorists in Afghanistan, Iraq and beyond’ (2002) 35 Cornell International Law Journal 533; Mary Ellen O’Connell, ‘Lawful Self-Defense to Terrorism’ (2002) 63 University of Pittsburgh Law Review 889; Thomas M Franck ‘Terrorism and the Right of Self-Defense’ (2001) 95 American Journal of International Law 839.

^[22] [2004] ICJ Rep 1 (‘Wall Advisory Opinion’).

^[23] Resolution on Illegal Israeli actions in Occupied East Jerusalem and the rest of the Occupied Palestinian Territory, GA Res ES-10/14, UN GAOR, 10^th emerg spec sess, 23^rd plen mtg, UN Doc A/RES/ES-10/14 (2003).

^[24] Wall Advisory Opinion, above n 22, [139].

^[25] For review and analysis of the ICJ’s view on self-defence in this case see Ruth Wedgwood, ‘The ICJ Advisory Opinion on the Israeli Security Fence and the Limits of Self-Defense’ (2005) 99 American Journal of International Law 52, 57-61; Sean D Murphy, ‘Self-Defense and the Israeli Wall Advisory Opinion: An Ipse Dixit from the ICJ?’ (2005) 99 American Journal of International Law 62.

^[26] See also the decision by the Court in Oil Platforms (Merits) [2003] ICJ Rep

<http://www.icj-cij.org/icjwww/idocket/iop/iopjudgment/iop_ijudgment_20031106.PDF> at 24 October 2005, where the ICJ also had occasion to consider whether US attacks upon Iranian Oil Platforms were justified on the basis of self-defence. For a stinging critique of that aspect of the decision from a US position see William H Taft IV, ‘Self-Defense and the Oil Platforms Decision’ (2004) 29 Yale Journal of International Law 295.

^[27] This point is noted in the Separate Opinion of Judge Kooijmans in Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory (Advisory Opinion) [2004] ICJ Rep 1, [35] where in reference to SC Res 1368 and 1373 it was noted:

The Security Council called acts of international terrorism, without any further qualification, a threat to international peace and security which authorizes it to act under Chapter VII of the Charter. And it actually did so in resolution 1373 without ascribing these acts of terrorism to a particular State. This is the completely new element in these resolutions. This new element is not excluded by the terms of Article 51 since this conditions the exercise of the inherent right of self-defence on a previous armed attack without saying that this armed attack must come from another State even if this has been the generally accepted interpretation for more than 50 years. The Court has regrettably by-passed this new element, the legal implications of which cannot as yet be assessed but which marks undeniably a new approach to the concept of self-defence.

See also the observations contained in the Declaration of Judge Burgenthal, [6].

^[28] Ian Brownlie, International Law and the Use of Force by States (1963), 257.

^[29] See eg John Westlake, International Law (1904) vol I, 299.

^[30] Brownlie, above n 28, 257. Other scholars in support of this view post 1945 included Derek W Bowett, Self-Defence in International Law (1958) 31, 58, 256, 269; Philip C Jessup, A Modern Law of Nations (1956) 166; and Julius Stone, Legal Controls of International Conflict (1954) 244.

^[31] Dinstein, above n 13, 167. However, Dinstein goes on to make a distinction between preventive self defence (ASD) and interceptive self defence: see above n 13, 172, where it is noted, ‘Whereas a preventive strike anticipates an armed attack that is merely “foreseeable” (or even just “conceivable”), an interceptive strike counters an armed attack that is “imminent” and practically “unavoidable’’’.

^[32] Brownlie, above n 28, 259.

^[33] See the discussion in T L H McCormack, Self-Defense in International Law: The Israeli Raid on the Iraqi Nuclear Reactor (1996); and A D’Amato, ‘Israel’s Air Strike Upon the Iraqi Nuclear Reactor’ (1983) 77 American Journal of International Law 584.

^[34] The Resolution was adopted on 19 June 1981. SC Res 487, UN SCOR, 37^th sess, 228^th mtg, UN Doc S/RES/487 (1981).

^[35] McCormack, above n 33, 286.

^[36] Dinstein, above n 13, 169.

^[37] Ibid 169.

^[38] Statement by Larry Speakes, White House spokesman, 15 April 1986.

^[39] Statement by President Reagan, 15 April 1986.

^[40] On these grounds, Dinstein argues that the US actions were part of a ‘defensive armed reprisal’, Dinstein, above n 13, 201; for further discussion on reprisals and their status under international law see W V O’Brien, ‘Reprisals, Deterrence and Self-Defense in Counterterror Operations’ (1989-90) 30 Virginia Journal of International Law 421.

^[41] In the Nicaragua Case the Court noted that ‘the lawfulness of a response to an imminent threat of armed force has not been raised’ and accordingly declined to consider the lawfulness of such action: Nicaragua Case, above n 14, [194].

^[42] The two cases were the Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons [1996] ICJ Rep 226, and the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory [2004] ICJ Rep 1.

^[43] There are numerous articles, essays, collections and books published in the wake of these events which give consideration to these issues from an international law perspective; see in particular Michael Byers, ‘Terrorism, The Use of Force and International Law After 11 September’ (2002) 51 International and Comparative Law Quarterly 401; Franck, above n 21; Christopher Greenwood, ‘International Law and the War Against Terrorism’ (2002) 78 International Affairs 301; Gilbert Guillaume, ‘Terrorism and International Law’ (2004) 53 International and Comparative Law Quarterly 537.

^[44] Interestingly, the law of jus ad bellum—the law concerning the right to use military force—proved to be less contentious following September 11 than the law of jus in bello—the law dealing with the conduct of an armed conflict. On the interpretation by the US and some of its allies of the principles of international humanitarian law and its application during the 2001 Afghanistan conflict, in particular, the characterisation of certain persons as ‘battlefield detainees’ not entitled to protections under the Geneva Conventions, see George H Aldrich, ‘The Taliban, Al Qaeda and the determination of illegal combatants’ (2002) 96 American Journal of International Law 891.

^[45] Robert Hill, John Bray Memorial Oration (2002) Department of Defence

<http://www.minister.defence.gov.au/2002/694281102.doc> at 17 November 2005. Similar thoughts are expressed in the view of the Legal Advisor to the US State Department: William H Taft IV, ‘Preemptive Action in Self-Defense’ (2004) 98 American Society of International Law Proceedings 331, 332 who argues that ‘[t]he concept of imminence in the traditional framework of self-defense must be revisited in the era of weapons of mass destruction (WMDs).’

^[46] National Security Strategy of the United States of America, above n 4, ii.

^[47] Ibid 14.

^[48] Ibid 15. These views have generated a significant debate in the academic literature, see eg Thomas M Franck, ‘Preemption, prevention and anticipatory self-defense: New law regarding recourse to force?’ (2004) 27 Hastings International and Comparative Law Review 425; David D Caron, ‘The rule-outcome paradox, madness cascades and the fog of preemption: Seeking the ‘best rule’ for the use of force’ (2004) 27 Hastings International and Comparative Law Review 481; Timothy Kearley, ‘Regulation of preventive and preemptive force in the United Nations Charter: A search for original intent’ (2003) 3 Wyoming Law Review 663.

^[49] National Security Strategy of the United States of America, above n 4, 15 asserted:

For centuries, international law recognized that nations need not suffer an attack before they can lawfully take action to defend themselves against forces that present an imminent danger of attack. Legal scholars and international jurists often conditioned the legitimacy of preemption on the existence of an imminent threat—most often a visible mobilization of armies, navies, and air forces preparing to attack.

^[50] On these variants see Elisabeth Zoller, ‘The Law Applicable to the Preemption Doctrine’ (2004) 98 American Society of International Law Proceedings 333, 334.

^[51] William H Taft IV The Legal Basis for Preemption (2002) Council on Foreign Relations Memorandum:

<http://www.cfr.org/publication/5250/legal_basis_for_preemption.html> at 17 November 2005.

^[52] Ibid.

^[53] Taft, above n 45, 332.

^[54] Ibid 333.

^[55] See SC Res 1441, UN SCOR, 56^th sess, 4644^th mtg, UN Doc S/RES/1441 (2002); this mandate was originally provided under SC Res 1284 (17 December 1999) establishing UNMOVIC (Phase I) (SC Res 1284, UN SCOR, 54^th sess, 4084^th mtg, UN Doc S/RES/1284 (1999).

^[56] See William H Taft IV and Todd F Buchwald, ‘Preemption, Iraq and International Law’ (2003) 97 American Journal of International Law 557, 557-558, where emphasis is given to the context including ‘the naked aggression by Iraq against its neighbours, its efforts to obtain weapons of mass destruction, its record of having used such weapons, Security Council action under Chapter VII of the United Nations Charter, and continuing Iraqi defiance of the Council’s requirements.’ Other views in support of the war can be found in John Yoo, ‘International Law and the War in Iraq’ (2003) 97 American Journal of International Law 563.

^[57] See Legal Advice to the Government of Australia, ‘Memorandum of Advice on the Use of Force Against Iraq, provided by the Attorney-General’s Department and the Department of Foreign Affairs and Trade, March 18, 2003’, at <http://www.pm.gov.au/iraq/displayNewsContent.cfm?refx=96> at 16 November 2005. George Williams and Devika Hovell, ‘Advice to Hon Simon Crean MP on the Use of Force against Iraq’ (2003) 4 Melbourne Journal of International Law 183; Grant Niemann, ‘Advice to Hon Simon Crean MP on the Use of Force Against Iraq’ (2003) 4 Melbourne Journal of International Law 190.

^[58] See SC Res 678, UN SCOR, 45^th sess, 2963th mtg, S/RES/678 (1990).

^[59] See SC Res 687, UN SCOR, 45^th sess, 2981^st mtg, S/RES/687 (1991).

^[60] SC Res 1441, UN SCOR, 56^th sess, 4644^th mtg, UN Doc S/RES/1441 (2002). The legal argument founded on pre-existing SC authorisation was outlined in Ruth Wedgwood, ‘The Enforcement of Security Council Resolution 687: The Threat of Force Against Iraq’s Weapons of Mass Destruction’ (1998) 92 American Journal of International Law 724.

^[61] See the discussion in Christine Gray, International Law and the Use of Force (2^nd ed, 2004) 270-279.

^[62] Report of the Secretary-General’s High-level Panel on Threats, Challenges and Change, A more secure world: Our shared responsibility (2004).

^[63] Ibid 48 [159].

^[64] Report of the Secretary-General (United Nations), In larger freedom: Towards development, security, and human rights for all (2005) 33 [122], UN Doc A/59/2005 (‘In larger freedom’).

^[65] Ibid 33 [124].

^[66] Ibid 33 [126].

^[67] 2005 World Summit Outcome, GA Res 60/1, 60^th sess, 8^th plen mtg, UN Doc A/RES/60/1 (2005) [2],[6].

^[68] Ibid [79].

^[69] Ibid [85].

^[70] Ibid [138-139].

^[71] Though care must be taken in overstating the weight to be attached to the incident given the American rebels had taken possession of Navy Island in the Niagara River nearly two weeks prior to the attack on the Caroline: see Jennings, above n 6, 83.

^[72] Zoller, above n 50, 334, who argues that whilst the Court refrained from taking an explicit position it took an implicit position on it nevertheless by doing away with the old customary law that had been ‘for centuries’ the legal support of preventive self-defense.

^[73] Zoller, above n 50, 336.

^[74] Rosalyn Higgins, Problems and Process: International Law and How we use it (1994) 242.

^[75] Zoller, above n 50, 336 quoting from the National Security Strategy, above n 4, 15.

^[76] In larger freedom, above n 64, 33 [124].

^[77] Dinstein, above n 13, 172.