The claim by the United States to a right of what has come to be known as “preemptive self defense” has provoked deep anxiety and soul-searching among the members of the college of international lawyers. Some have feared that the claim signaled a demand for the prospective legitimization of “Pearl Harbor” types of actions, that is, sudden, massive, and destructive military actions “out of the blue,” by one state against another in the absence of a state of war, with the objective of militarily neutralizing or even eliminating a latent or potential adversary. Since some public intellectuals within the American political system had recommended such a strategy with respect to the People’s Republic of China in the midst of the Cold War,’ the anxiety could not be dismissed as entirely unfounded or even hysterical.
Nor could it be ignored as if it were some sort of exclusively American aberration that could be tolerated as the idiosyncrasy of one state. From the earliest unilateral claims to a continental shelf, a copycat or mimetic dynamic in modern international law has taken shape whenever an enhancement of state power has become available, so that the possibility of similar claims to an expanded notion of preemptive self-defense by many other states could not be excluded. Indeed, while the United States may now have retreated somewhat from its 2002 broad claim to preemption, various other states (including some with nuclear weapons) have adopted the preemptive self-defense claim as their own. If the U.S. claim posed potentially destabilizing consequences for world order, how much more so would proliferation of the claim? The United Nations Charter’s prescription with respect to the use of force is essentially binary: either a use of military force is in self-defense, as that concept is conceived in the Charter, in which case it is lawful, or it is not, in which case it is unlawful. As for the right to resort to military measures in self-defense, it materializes only when the state invoking it has suffered an “armed attack,” a stricture that does not even extend to the Caroline doctrine of anticipatory self-defense. 2
During the Cold War, the practice of low-level protracted conflicts placed considerable stress on the Charter regime, and those charged with its application were obliged to ignore the overt and explicit nuclear threats between the superpowers that had come to constitute the system of strategic deterrence. But despite these problems, the International Court of Justice 3 and most international lawyers have steadfastly insisted on the strict application of the Charter * Of the Board of Editors; and Yale Law School, JD 2007, respectively. The authors thank Margaret Hellerstein for research assistance. ‘William Buckley, A Noted Liberal Agrees: Lets Destroy Peking’ A- Threat Now, L.A. TIMES, Dec. 16, 1964, at A6, available in ProQuest Historical Newspapers. 2 See R. Y. Jennings, The Caroline andMcLeod Cases, 32 AJIL 82 (1938); see also W. Michael Reisman, International Legal Responses to Terrorism, 22 HOUS. J. INT’L L. 3 (1999) (discussing possible current applications). 3 See, e.g., Military and Paramilitary Activities in and Against Nicaragua (Nicar. v. U.S.), Jurisdiction and Admissibility, 1984 ICJ REP. 392 (Nov. 26); Military and Paramilitary Activities in and Against Nicaragua (Nicar. v. U.S.), Merits, 1986 ICJ REP. 14 (June 27); Oil Platforms (Iran v. U.S.), Preliminary Objections, 1996 ICJ REP. 803 (Dec. 12); Oil Platforms (Iran v. U.S.), Merits, 2003 ICJ REP. 161 (Nov. 6). HeinOnline — 100 Am. J. Int’l L. 525 2006 THE AMERICAN JOURNAL OF INTERNATIONAL LAW regime, most recently in the Congo v. Uganda decision, 4 which is discussed below.
Yet if customary international law is in the process of accommodating the U.S. claim to a right of preemptive action-a distinct possibility given the adoption (both full and partial) of the U.S. claim by other significant states-the possibility of future invocations is increased. I. The claim to preemptive self-defense is a claim to entitlement to use unilaterally, without prior international authorization, high levels of violence to arrest an incipient development that is not yet operational or directly threatening, but that, if permitted to mature, could be seen by the potential preemptor as susceptible to neutralization only at a higher and possibly unacceptable cost to itself.5 Preemptive self-defense differs from anticipatory self-defense in that those contemplating the latter can point to a palpable and imminent threat. Thus, anticipatory self-defense (which was, in our view, not in the contemplation of the drafters of the Charter, though claimed by many to have been grafted thereon by subsequent practice) is at least akin to the armed attack requirement of Charter Article 51, because there may be palpable evidence of an imminent attack. A claim for preemptive self-defense can point only to a possibility among a range of other possibilities, a contingency. As one moves from an actual armed attack as the requisite threshold of reactive self-defense, to the palpable and imminent threat of attack, which is the threshold of anticipatory self-defense, and from there to the conjectural and contingent threat of the mere possibility of an attack at some future time, which is the threshold of preemptive self-defense, the self-assigned interpretive latitude of the unilateralism becomes wider, yet the nature and quantum of evidence that can satisfy the burden of proof resting on the unilateralism becomes less and less defined and is often, by the very nature of the exercise, extrapolation and speculative.
The evolution of weapons systems that are ever more rapid and destructive and that may be initiated without warning or with very narrow warning windows has been invoked as a justification for preemption. But ultimately the central issue is assessment by the risk-averse security specialists of one international actor of the intentions of another actor who has or may acquire the weapons. In an international system marked by radically different cultures, values, and, as a consequence, factual perceptions and their strategic assessments, an act of preemptive self-defense, based upon one actor’s self-perceived good faith conviction, will often look like serious or hysterical misjudgment to some actors and like either cynical or self-deluded, naked aggression to others. When a major international actor claims a new right or its adjustment or termination, the implications for changing customary international law loom especially large, for, at every level of social organization, the making of law, much more than its institutional applications, is in great part political; doctrines of sovereign equality notwithstanding, the actions of a great power may be more generative of law than those of smaller states.
The question that is posed in this article is whether, in the period since 2002 when the United States began elaborating its broadest claim, the international legal system has begun to incorporate it, in whole or in part, even as the United States may have ‘ Armed Activities on the Territory of the Congo (Dem. Rep. Congo v. Uganda) (Int’l Ct. Justice Dec. 19,2005) [hereinafter Congo v. Uganda]. 5 The discourse has used different terms to describe this claim throughout the debate on the legality of the use of force. For an interesting discussion, see YORAM DINSTEIN, WAR, AGGRESSION, AND SELF-DEFENCE (4th ed. 2005). 6 The inherent difficulty of such exercises is apparent in Taft and Buchwald’s contention that the U.S. invasion of Iraq in 2003 was a lawful use of preemptive military self-defense. William H. Taft IV & Todd F. Buchwald, Preemption, Iraq, and International Law, 97 AJIL 557 (2003). [Vol. 100:525 HeinOnline — 100 Am. J. Int’l L. 526 2006 CENTENNIAL ESSAYS retreated from it. If its incorporation has in fact begun, a pertinent question for the jurist is whether the change has significantly affected world public order. II. Over the course of the twentieth century, a fair number of U.S. actions that might be characterized as preemptive self-defense-such as military actions in Haiti and the Dominican Republic before World War I, the military strikes against Tripoli in 1975, and the shelling of Lebanon after the destruction of the U.S. marine barracks-are better characterized as responses to ongoing military conflicts.
Recent decades have also seen an increase in resort to military actions to prevent or end crimes against humanity, but these actions were invoked under the rubric of humanitarian intervention, not preemptive self-defense. One possible forerunner of the U.S. unilateral claim to preemptive self-defense would be the Cuban missile crisis, but that was marked by preventive nonmilitary action that shifted the option of an overt military response to the other party.7 In the modern era, explicit claims to preemptive uses of military force have been associated preeminently with the administration of George W. Bush, but they were actually pressed by previous administrations, as well as by other states. In the United States, one can trace a series of indicators of a shift in official thinking toward preemptive military strategies well prior to the attacks of September 11, 2001. In 1984 President Ronald Reagan issued a classified national security decision directive outlining his administration’s response to terrorism. An unclassified extract explains: State-sponsored terrorist activity or directed threats of such action are considered to be hostile acts and the U.S. will hold sponsors accountable. Whenever we have evidence that a state is mounting or intends to conduct an act of terrorism against us, we have a responsibility to take measure [sic] to protect our citizens, property, and interests.8 Two years later, against the continuing backdrop of suspected Libyan governmental support for terrorist attacks, a classified directive raised the prospect of unilateral military action to prevent terrorist attacks. National Security Decision Directive 207 stated: The U.S. Government considers the practice of terrorism by any person or group a potential threat to our national security and will resist the use of terrorism by all legal means available. The United States is opposed to domestic and international terrorism and is prepared to act in concert with other nations or unilaterally when necessary to prevent or respond to terrorist acts. States that practice terrorism or actively support it, will not be allowed to do so without consequence. Whenever we have evidence that a state is mounting or intends to conduct an act of terrorism against us, we have a responsibility to take measures to protect our citizens, property, and interests.
The authors disagree with some scholarly characterizations of the U.S. blockade of Cuba during the 1962 Cuban missile crisis as preemptive self-defense. The claim to preemptive self-defense, at its core, is an asserted legal right to use offensive military force against a target that does not yet, but may in the future, pose a threat. Although the blockade could be characterized as preemptive action or as a measure of self-defense, it is not preemptive self defense. See Ruth Wedgwood, The Fall of Saddam Hussein: Security Council Mandates and Preemptive Self-Defense, 97 AJIL 576, 584-85 (2003). 8 Extract of National Security Decision Directive 138 (signed Apr. 3, 1984), available at (the full directive is still classified). ‘ National Security Decision Directive 207, The National Program for Com batting Terrorism (Jan. 20, 1986) (formerly top secret)
Although initially confined to classified documents, the new policy was explicitly discussed in newspaper articles and in speeches by high administration officials,1 ” a widely used and internationally legally noted method for establishing national positions-indeed, even for assuming international obligations. 1 In what later became known as the “Shultz doctrine,” Secretary of State George Shultz argued for the right to take limited military action to address terrorist threats while they are still “manageable.” In the wake of the recent attacks at the Rome and Vienna airports, we have heard it asserted that military action to retaliate or preempt terrorism is contrary to international law.
Some have suggested that even to contemplate using force against terrorism is to lower ourselves to the barbaric level of the terrorists. I want to take this issue head on. Unlike terrorists and communist guerrillas, we do not believe the end justifies the means. We believe in the rule of law. This nation has long been a champion of international law, the peaceful settlement of disputes, and the UN Charter as a code of conduct for the world community.1 2 Noting the specific exception to the Charter’s restrictions on the use or threat of force for the right of self-defense, Secretary Shultz called it absurd to argue that international law prohibits us from capturing terrorists in international waters or airspace; from attacking them on the soil of other nations, even for the purpose of rescuing hostages; or from using force against states that support, train, and harbor terrorists or guerrillas.
International law requires no such result. A nation attacked by terrorists is permitted to use force to prevent or preempt future attacks, to seize terrorists, or to rescue its citizens when no other means is available. The law requires that such actions be necessary and proportionate. But this nation has consistently affirmed the right of states to use force in exercise of their right of individual or collective self-defense.13 Shultz strongly foreshadowed the position espoused by the Bush administration in 2002 by arguing that [a] lies and friends may object to our action–or say they object. But this cannot be decisive. Striking against terrorism in the Middle East, for example, is bound to be controversial. But the worst thing we could do to our moderate friends in the region is to demonstrate that extremist policies succeed and that the United States is impotent to deal with such challenges. 4 Well over a year earlier, in October 1984, Secretary Shultz had already advocated the development of a domestic consensus on the right to use force preemptively in terrorist “gray areas” of fact and law: The heart of the challenge lies in those cases where international rules and traditional practices do not apply. Terrorists will strike from areas where no governmental authority 10 See, e.g., Robert C. Toth, Preemptive Anti- Terrorist Raids Allowed, WASH. POST, Apr. 16, 1984, at A19. 1 Nuclear Tests (Austl. v. Fr.), 1974 ICJ REP. 253, 267-68 (Dec. 20); see also W. Michael Reisman & Mahnoush H. Arsanjani, The Question of Unilateral Governmental Statements as Applicable Law in Investment Disputes, 19 ICSID REV. 328 (2004). 12 George P. Shultz, Secretary of State, Low-Intensity Warfare:
The Challenge of Ambiguity, Address at National Defense University (Jan. 15, 1986), BUREAU OF PUBLIC AFFAIRS, U.S. DEP’T OF STATE, CURRENT POL’Y NO. 783, reprinted in 25 ILM 204, 206 (1986). 13 Id., 25 ILM at 206. 14 Id., 25 ILM at 205. [Vol. 100:525 HeinOnline — 100 Am. J. Int’l L. 528 2006 CENTENNIAL ESSAYS exists, or they will base themselves behind what they expect will be the sanctuary of an international border. And they will design their attacks to take place in precisely those “gray areas” where the full facts cannot be known, where the challenge will not bring with it an obvious or clear-cut choice of response. In such cases we …. will have to examine the full range of measures available to us to take. The outcome may be that we will face a choice between doing nothing or employing military force.
Terrorism is being used by our adversaries as a modern tool of warfare. We can expect more terrorism directed at our strategic interests around the world in the years ahead. To combat it, we must be willing to use military force.’ 5 Claims of a right to unilateral preemption were more muted in the administration of George H. W. Bush from 1988 to 1992. Indeed, directly after Shultz’s speech in October 1984, then vice president Bush (perhaps not coincidentally one of the few leaders in the administration to have had battle experience) publicly disagreed with the policy. Vice President Bush argued, “I think you’ve got to pinpoint [the response to terrorism], and we’re not going to go out and bomb innocent civilians or something of that nature.”1’6 The claim to a right of preemptive self-defense was not limited to Republican administrations. In the National Security Strategy for a New Century, published by the Clinton administration in October 1998, the possibility of a claim to a right of preemption was indicated, but more by implication: Adversaries will be tempted to disrupt our critical infrastructures, impede continuity of government operations, use weapons of mass destruction against civilians in our cities, attack us when we gather at special events and prey on our citizens overseas. The United States must act to deter or prevent such attacks and, if attacks occurs [sic] despite those efforts, must be prepared to limit the damage they cause and respond decisively against the perpetrators. 17 In 2000, however, the Clinton administration issued a new security document,
A National Security Strategy for a Global Age, in which more explicit attention was given to terrorism. With respect to possible nuclear attacks from a symmetrical adversary, the policy continued to be reactive: “Our military planning for the possible employment of U.S. strategic nuclear weapons is focused on deterring a nuclear war and it emphasizes the survivability of our nuclear systems, infrastructure, and command, control, and communications systems necessary to endure a preemptive attack yet still deliver an overwhelming response. ” “‘ A strategic posture of reaction rather than pro-action would be consistent with Article 51. But in the same document, preemptive action is raised as a means of combating asymmetrical foes who are using the techniques of terrorism. The U.S. “aggressive response to terrorism” is described as follows: Our strategy pressures terrorists, deters attacks, and responds forcefully to terrorist acts. It combines enhanced law enforcement and intelligence efforts; vigorous diplomacy.