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The Bush Administration's Doctrine of Preemption (and Prevention): When, How, Where?

February 1, 2004
Council on Foreign Relations


The Boston Term Member group of the Council on Foreign Relations hosted three roundtables in the late spring of 2003 to examine the concept of “preemption” contained in the President’s National Security Strategy Report. Panelists included Stephen Walt and Ashton Carter of the Kennedy School of Government at Harvard University, Richard Betts of Columbia University, and Michael Glennon of The Fletcher School of Law and Diplomacy at Tufts University. This paper presents our analysis and findings. The paper was written by Jon Rosenwasser, with editorial assistance from and David Fairman, and advice and comment from Walid Chamoun, William Foote, Chris Howard, Scott Nathan, , Jeff Taliaferro, and Jonathan Zittrain.

A key concept underlying President George W. Bush’s National Security Strategy (NSS), issued 20 September 2002, is that of “preemption,”[1] defined as “preemptive and preventive action.” The NSS notes that terrorism and weapons of mass destruction in the hands of rogue states have made preemption more attractive as a policy option, but it does not lay out specific criteria or guidelines for determining when the U.S. should carry out preemptive attacks. In addition, the NSS seeks to build more integrated intelligence capabilities, to coordinate with allies to form a common assessment of the most dangerous threats, and to transform our military forces to ensure our ability to conduct rapid and precise operations to achieve decisive results. It offers few concrete recommendations to achieve these objectives.

This paper assesses the NSS, seeking to provide analytical depth to assist policymakers in determining when, where and how preemption might constitute sound policy and what tools need strengthening for its effective implementation. First, it examines the recent rise to prominence of preemption as national policy. Second, it outlines the intelligence, diplomatic and military implications of a policy of preemptive and preventive war. Finally, it offers recommendations for refining the policy of preemption and the capabilities needed to implement it.

I. Why Preemption Now?

Until the end of the 19th century, the United States was generally reluctant to use military force abroad, with limited exceptions, to defend American interests and expand the national territory. During the 20th century, the U.S. became a great power, and conducted many military interventions around the world. Nevertheless, U.S. policymakers have generally stated a preference to use force only as a last resort. Even when faced with imminent threats, policymakers have rarely used preemption (defined as the use of U.S. military force to eliminate credible and imminent threats to U.S. interests before enemy attacks occur) due to organizational and political obstacles.[2] The U.S. has arguably undertaken only three preemptive actions in the last century.[3]

But the changing nature of the international system since the end of the Cold War seems to have changed the calculus of action and the desirability of preemption. The proliferation of weapons of mass destruction (WMD), the increasing number of failing states, and the rise of terrorism as a coordinated, global phenomenon have increased the level of threat to American security. Simultaneously, the demise of the Soviet Union and the absence of any countervailing power or bloc have lowered the perceived costs of employing force and intervention abroad.

The shock of the 9/11 attacks demonstrated that the U.S. is vulnerable to mass casualties from terrorist attacks. The U.S. needs to intensify its efforts at defending the homeland and forestalling emerging threats. Two distinct threats have demanded a more robust response. One is the advent of states developing WMD to threaten their neighbors and upset regional and perhaps global balances of power. The other is terrorists armed with modern technologies from airplanes converted into flying bombs or “dirty” nuclear devices. The most potent threat is a rogue state not subject to classic means of deterrence and armed with WMD.

The NSS outlines several strategies for reducing terrorist and rogue state threats, including diplomatic pressure on states and non-state actors (e.g. financial institutions and religious organizations) to deny terrorists sponsorship, support, and sanctuary; building an international consensus that terrorism and the use of WMD are as illegitimate as piracy and genocide; supporting moderate and modern forms of government, especially in the Muslim world; and public diplomacy. But the NSS emphasizes “preemption” as the policy of choice.

The difference between preemptive war and preventive war is not a matter of semantics. Rather, it is a matter of timing that has implications for whether an act is justified or not. Traditionally, preemption constitutes a “war of necessity” based on credible evidence of imminent attack against which action is justified under international law as enshrined in the self-defense clause (Article 51) of the UN Charter. But the Bush administration has expanded the definition to include actions that more closely resemble preventive war. Preventive wars are essentially “wars of choice” that derive mostly from a calculus of power, rather than the precedent of international law, conventions and practices. In choosing preventive wars, policymakers project that waging a war, even if unprovoked, against a rising adversary sooner is preferable to an inevitable war later when the balance of power no longer rests in their favor. The proposition gains traction when that enemy state is arming itself with WMD, or credibly threatens the supply of a critical resource such as oil, and national intelligence indicates that the enemy intends to harm one's own state.

The Bush administration justifies this expanded definition of preemption based on today’s circumstances. The nature of modern weaponry, from long-range missiles to information warfare, has eroded the protection geography traditionally provided the U.S. Compartmentalized terrorist cells can now move across national boundaries and surface near or within U.S. borders to wreak havoc. Their plans and capabilities are revealed only after the fact: 9/11 serves as the most glaring example of the need to adopt a more forward-leaning posture. As the NSS states: “We must adapt the concept of imminent threat [that justifies preemption] to the capabilities and objectives of today’s adversaries. Rogue states and terrorists do not seek to attack us using conventional means…Instead, they rely on acts of terror and, potentially, the use of weapons of mass destruction— weapons that can be easily concealed, delivered covertly, and used without warning.” In other words, in today’s world of stateless terrorists and rogue states with potential access to dangerous technologies, the length of the fuse has shortened, rendering the difference between preemption and prevention moot.

There is little doubt that preemptive and preventive war can merge, as in the case of actions against states that are harboring terrorists who have a standing order to destroy those parts of civilization they abhor. However, the distinction between prevention and preemption is important because states are sanctioned and legitimized by the international community. Should a state take a preemptive action against a threat not deemed imminent by the international community, then it may be seen as a bully or even as a rogue state both at home and abroad. Being labeled as a bully or rogue may deprive the state of needed intelligence, diplomatic, military and political support in its efforts to secure itself. Thus, the international community’s judgment that the U.S. has acted to prevent rather than preempt a conflict may have significant negative consequences for the U.S. even if the U.S. achieves its immediate goal of eliminating a perceived threat.

Regardless of this definitional question, Stephen Walt points out that the attractiveness of both preemptive and preventive war has increased for two reasons. The first reason is functional. The U.S. now has an offensive capability of unmatched versatility and strength. Washington’s defense budget for fiscal year 2003 exceeds $450 billion, more than the next 40 countries’ military budgets combined,[4] It can deploy its military assets globally and on short-notice to conduct offensive operations. This military capability provides policymakers with unprecedented military options for preemptive action anywhere in the world. The second reason preemption is more attractive stems from the current preponderance of U.S. influence in international affairs. The U.S. faces few political barriers to action. Some states may complain about America as the global bully; but rarely do they counter U.S. power for fear of retribution in other arenas, such as trade, or because of overriding common interests, such as fighting terrorism.

II. When to Engage in Preemptive or Preventive War: The Role of Intelligence

Intelligence is central to legitimating military action. If the U.S. is unable to demonstrate to the world that it has acted to preempt a credible threat (i.e. a state or terrorist group with intention, capability and concrete plans to attack U.S. interests), American authority abroad erodes and a president’s standing at home wanes.

Intelligence plays very different roles depending on whether the context is preemptive war or preventive war. To justify preemptive war both to the international community and to the American people, the U.S. must have solid evidence that not only does a state have the means of attack, but also the intention to do so imminently. According to Richard Betts, obtaining clarity about intent is often difficult.[5] The picture is often murky because of conflicting state signals, inadequate insight into the inner workings of enemies’ top leadership, or imperfect understandings of the goals and methods of terrorist organizations. Military maneuvers along a contested border can constitute a readiness drill as easily as the buildup to a first wave of attack. Sophisticated sensors that track troop and weaponry movements are limited by the effects of camouflage or subterfuge. At home, the U.S. still has poor insight into the operations of terrorist cells despite the creation of the Department of Homeland Security and enactment of the USA Patriot Act. The espionage network remains thin in critical areas of the world where anti-Americanism runs deep, in part due to massive cutbacks after the Cold War and in part due to our failure to foster knowledge of and a presence in the Middle East and other Islamic cultures.

For preventive wars, on the other hand, intelligence has a more circumscribed role. The decision to wage preventive war rests on an assessment of likely future conflict with a state,[6] based on an assessment of trends and risks (e.g. growing military power and irredentist claims on the territory of a U.S. ally) rather than immediate intentions, capabilities and plans. As Betts argues, the more salient analysis is a long-term calculation of the future balance of power, where political judgment and informed speculation, not hard intelligence data, shape the decision-making process. Policymakers may still use intelligence to make the future appear more certain than it could be, thus steering the country towards a more belligerent policy. However, no intelligence estimate can provide adequate clarity on the future state of international relations to serve as a reliable guide to justify preventive war. Indeed, history is replete with examples of states preparing for preventive action in ways that fuel the very conflict they seek to avoid. A further challenge to intelligence is the need to consider unintended consequences of preventive action, including the creation of new enemies or the formation of new alliances hostile to American interests.

Three specific recommendations flow from this analysis. First, to improve intelligence about terrorist intentions, capacities and plans, the U.S. needs to improve its capacity to penetrate terrorist organizations operating in the U.S. and around the world, particularly in Islamic cultures. Domestically, the USA Patriot Act contained significant if not contention-free first steps, including the registration of non-permanent foreign residents and international students. But more aggressive measures should be considered, including monitoring the borders with remote devices such as unmanned aerial vehicles, establishing a national identity card system, and linking federal databases better to facilitate the assembly of a suspected terrorist profiles. American society appreciates the domestic terrorist threat and accepts any modest incursions on civil liberties that these steps might impose. However, further curtailments of legal rights of due process, long a bedrock of constitutional democracy, should be avoided. While measures such as detention of illegal immigrants might offer occasional, marginal assistance to federal investigators, they cause more harm by undoing our fabric of basic legal protections.

Internationally, the intelligence community needs to recruit and train a new cadre of country and regional experts - both to conduct analysis as well as to deploy in the field. The Army and of late, the Air Force, have successfully groomed regional experts in their respective Foreign Area Officer (FAO) programs whereby mid-career military professionals serve consecutive tours focusing on a particular geographic area. Assignments include graduate school, language training, and attaché or geo-division work at State, the Pentagon, an intelligence agency or the White House. The U.S. intelligence apparatus was heavily focused on the Soviet threat during the Cold War. In the post-Cold War period, the intelligence community has retrenched along with the military, with massive personnel reductions and a movement away from human intelligence and towards technical sources. The threats we encounter today require the U.S. to develop talent here at home and recruit reliable sources on the ground in other countries. Integral to this effort should be enactment of the modern equivalent to the National Defense Education Act of 1958: legislation designed to raise the level of national expertise in areas such as terrorism studies, language skills, and Islamic studies.

Second, great efforts must be made to insulate the intelligence community from political manipulation. The integrity and credibility of our intelligence agencies rest on their ability to offer unvarnished assessments free of political pressure. When intelligence is politicized or perceived as politicized, it becomes nearly useless as a tool for policy planning or public diplomacy.[7] Furthermore, each controversy over the politicization of intelligence makes it more difficult for future administrations to gain the trust of the American people, Congress and/or the international community. Ingrained cynicism about intelligence may be as great a long-term threat to national security as any terrorist group or rogue state.

Third, if an American administration believes that the U.S. must act preventively against another state, that administration must make a good faith effort to distinguish “hard” intelligence of intentions and capabilities from more subjective analysis and political judgment of longer-term trends or emerging threats. Well-delivered analysis of long-term trends can be just as influential and credible as hard intelligence: Kennan’s Long Telegram and “X” article in Foreign Affairs together formed the basis for a 45 year strategy of containment. Presidents and their administrations should meet that very high standard of analysis in presenting preventive strategies to the Congress, the American people and the international community.

III. The Role of Diplomacy and Politics

Diplomacy and politics play a major role in determining whether, how and where to engage in preemptive or preventive war. The UN Charter is the closest approximation of an international consensus on the conditions under which states may use force, although its standing has eroded in recent years. Article 2, paragraph 4 of the UN Charter establishes the norm that states may not violate each other’s territorial integrity, although it does provide exceptions. Chapter 7, article 39, posits that in the face of a threat to the peace, a breach of the peace or an act of aggression, the UN Security Council - not individual states - can act preemptively. An individual state may only invoke Article 51 and act in self-defense after it has been attacked. The UN Charter does not give individual states any right of preemption, let alone prevention. Under all circumstances, the UN Charter views preventive war as illegitimate.

Underlying these clauses is the assumption that a muscular UN constabulary force would respond readily, quickly and effectively to violations of the non-intervention norm. Given the inability of the U.N. to secure borders and states’ desire for self-protection, the U.S. and other states continue to arrogate to themselves the right of preemption. The UN system often cannot muster the political will or military muscle swiftly enough to deter and if necessary defeat states bent on aggression (e.g. Iraq in 1990). And sometimes states have legitimate disagreements about the nature of a threat or how to cope with it, leading one or more parties to act outside the UN apparatus (e.g. Kosovo in 1999 and Iraq in 2003). Some cite such evidence to conclude that the UN’s regulation of force is a dead letter, a postwar experiment that has failed.[8] In this view, the NSS is simply a bold statement of reality: the U.S. reserves the right to act preemptively or preventively, with others as appropriate, but alone if necessary. The consequence of this shift in views on the use of force is that the U.S. will increasingly use force unilaterally, or in highly tailored coalitions of the willing, rather than through institutionalized settings like the UN or even a regional security organization like NATO.

The NSS’s policy of preemption poses diplomatic opportunities and risks. It provides the opportunity to rid the U.S. and the world of dangerous threats including the proliferation of WMD and global terrorism and thus ultimately advance liberal democratic principles. In addition, successful preemptive or preventive wars can potentially have a two-fold demonstration effect. On the one hand, they can signal what constitutes unacceptable behavior. For example, forcefully dealing with al Qaeda by expelling the Taliban has spoken volumes to other states about the consequences of harboring and aiding terrorist groups. On the other hand, using military force to import liberal democracy can set in motion the winds of political change that blow across an entire region. One hope is that the overthrow of Saddam Hussein will allow Iraq to become a pluralist democracy, triggering a process of liberalization in other parts of the Middle East, including states that sponsor anti-American terrorist groups.

However, there are significant political risks of a doctrine of preemptive or preventive war, especially when it is codified in a publicly circulated presidential document. First, it may in fact fuel rather than deter WMD proliferation. Threatened with preemptive action, states that are foes of the U.S. have very strong incentives to acquire WMD to deter U.S. attack. Indeed, the lesson states cull from Iraq may not be to give up aspirations for WMD, but rather to obtain them as soon as possible. This rationale is most evident with North Korea’s proclamation of its intention to expand its nuclear capability. In the fight against WMD proliferation, Ashton Carter argues that war, whether preemptive or preventive, is not the only option and rarely is it the best option. For example, the U.S. has successfully steered most of Europe, Japan and South Korea away from obtaining nuclear weapons not through force but through treaties, provision of nuclear monitoring and early warning systems, and other measures. Likewise, the U.S. has used diplomatic and economic incentives to forestall or reverse the WMD ambitions of countries such as South Africa, Ukraine and Argentina. For these countries, methods like the Nunn-Lugar program, which offers to buy back plutonium, have proven effective without the threat of military force. Only in the case of committed proliferators might preemptive or preventive war prove appropriate, but as a last resort rather than a first choice.

Second, a preemption doctrine that opens the door to preventive war presents several geostrategic risks for the U.S. It portrays America as a revisionist state, no longer content with the status quo in the international system. Dating back to World War II, the U.S. has been the linchpin to creating rules and norms to guide international behavior. If preemption is applied to situations that pose credible threats to that agreed framework— such as terrorists or states that violate the non-proliferation norm— then the U.S. may reinforce the principles of peace and justice in international relations. But if the doctrine is wielded for other more parochial, ideological or speculative reasons, the legitimacy of American power frays. As a result, instead of fueling respect for and emulation of American values and practices, the U.S. might lead its friends and erstwhile allies toward obstructionist policies (e.g., denying basing or overflight rights, as Turkey did in the Iraq war), non-compliance in other areas of mutual concern (e.g., being less willing to support the war on terrorism, as reportedly was the case with Saudi Arabia once the momentum to topple Saddam was set in motion) or efforts to balance American power (e.g., deepening regional pacts like the European Union). Further, if other states conduct preemptive or preventive military actions in ways that run counter to American interests, the U.S. will have little diplomatic credibility in opposing them.[9]

Because of its tilt toward unilateral action, the NSS potentially undermines international organizations as mechanisms to orient and enforce global rules the U.S. itself helped establish. The Bush administration has discounted multilateral approaches to foreign policy, whether it be the rejection of the Kyoto Protocol on climate change, the shelving of the Comprehensive Test Ban Treaty or the unwillingness to use NATO in the war in Afghanistan. With only the British at its side, the Iraq campaign represented yet another episode of the U.S. acting outside of the multilateral framework.

The Bush administration implicitly believes this turn away from multilateralism will either not harm or will in fact advance American interests. The post-conflict situation in Iraq leads to a different conclusion. Without significant numbers of international troops to help, roughly one-half of the deployable U.S. Army, or 180,000 of 300,000 active personnel, is now tasked to Iraq. However, the Congressional Budget Office estimates that in steady-state, the Army can support a deployment of only 3 to 5 2/3 brigades without withdrawing from other global commitments.[10] If this situation lasts for much longer, Michael O’Hanlon warns that the U.S. Army will “break.”[11] The pace and scope of Iraq’s economic recovery has been hobbled by the lack of participation by international non-governmental organizations. And as every day passes with the U.S., rather than an international force, as the occupying force, the Arab world’s belief in America’s imperialistic intentions in the region intensifies.

This analysis leads to three main conclusions. First, and most importantly, the stark declaratory nature of a policy of preemptive and preventive war serves more as a constraint on U.S. foreign policy than a trusty guidepost. The practice of U.S. foreign policy is not a series of independent actions, but actions interlinked over time, across areas of the world, with impacts for domestic politics and broader international relations. What the U.S. does today will reverberate for decades to come, especially on matters of war and peace. A formulaic approach to such complex decisions, while seemingly clarifying, may in fact create obstacles to realistic assessment of how to best advance America’s interests in specific situations. The U.S. will always retain the option to use military force in defense of its interests. But it may not be the best option given the particular circumstances. Like humanitarian intervention, the decision to embark on a preemptive or preventive war must be context-specific and made on a case-by-case basis.

Second, preemptive or preventive war must not constitute the sole policy option for stopping the proliferation of WMD. Different proliferators present different challenges, whose unique characteristics must be assessed and addressed accordingly. Force is sometimes the wise strategy; other times it can lead to catastrophic consequences. The Bush administration appears to be recognizing these nuances in the perplexing North Korea context and is downplaying the likelihood of military action to cope with Pyongyang’s nuclear intentions.

Third, international organizations are integral to maintaining a high level of cooperation among states. To the extent that they induce cooperation and constrain unruly behavior, they should be applauded. But their enduring value is in addressing problems that no state can tackle alone, included among them proliferation of WMD, global terrorism and international public health epidemics. While unilateral steps might prove beneficial on occasion, over the long-term the ability to rise to these challenges will hinge on the commitment of the international community’s member-states to work together. Dismissing multilateralism because of the difficult negotiations required to accommodate various perspectives may bring freedom of action in the short run but impose serious constraints on American action over the long run.

IV. Arming for Preemptive and Preventive War

The U.S. military stands as the preeminent armed force in the world. No other country can bring so much combat power to bear to any point on the planet so quickly. Since the end of the Cold War, the U.S. military has been slowly transforming to a lighter, more agile, more lethal and more deployable force. Combat units are more expeditionary and versatile today. The missions of preemptive and preventive war present new challenges to military planning that policymakers need to consider, especially given other national priorities (e.g. reducing record-setting deficits of over $450 billion per year, reigniting a stagnant American economy, and addressing domestic priorities such as prescription drug benefits for the elderly).

At least four issues are critical to the structure of U.S. armed forces in light of the NSS’s preemptive doctrine. First, acting unilaterally will require the creation of larger forces and assets with greater range than acting multilaterally. Given the difficulty in securing widespread international support for most forms of preemptive and preventive war (except in the most egregious cases), the U.S. must increasingly plan on deploying without substantial contributions from other states, including troops, capabilities, and overflight and basing rights.

Second, military doctrine must become far more flexible and agile. It must cope with geographic and political circumstances for which advance planning may never be sufficient, from engaging a traditional land-based, armored force motivated by secular nationalism to combating guerrilla forces lodged in the mountains animated by Islamist fundamentalism. The Special Operations Command has slowly grown in bureaucratic clout and political profile since its creation in the 1980s because of its leading role in dealing with non-traditional scenarios, yet its integration into the process of developing joint warfighting doctrine remains incomplete. In addition, doctrine must seamlessly shift from invasion to post-conflict reconstruction, from breaking things to providing security so that political transformation can occur. The glib pronouncement that the U.S. does not do nation-building belies reality; for without the commitment to provide effective and accountable instruments of government risks winning the war but losing the peace.

Third, military force structure needs tailored modification. The need under preemptive and preventive war for rapid insertion under clandestine cover dictates a greater reliance on Special Forces. In addition, the need for maintaining a sustained post-conflict presence translates into a larger army. Six months after President Bush declared the cessation of major combat operations in Iraq, the U.S. has 147,000 troops on the ground, with plans to maintain a deployment of over 100,000 for at least another year. Lastly, built into combat units must be a larger component of foreign area officers with a deeper cultural and linguistic expertise. As our experience in Afghanistan showed, an ability to work intimately with local militias aligned with U.S. interests was critical to mission success.

Fourth, the capabilities of the U.S. military need added depth in intelligence collection. Satellites can provide only limited coverage with no greater than about 3-foot resolution in predictable orbits. Unmanned aerial vehicles (UAVs) have great promise to provide persistent coverage of hot-spots with far greater resolution, yet few have been deployed. Predator and other UAVs could have blanketed Afghanistan and Iraq before and after the U.S. invasion to provide detailed intelligence on enemy troop movements, including the flights of Osama bin Laden and Saddam Hussein. Instead, U.S. forces ran into numerous ambushes in their attempts to track down these two most wanted men on the planet.

In sum, the doctrine of preemption as outlined in the NSS does reflect and respond to important changes in the balance of international threats and opportunities. Yet declaring, interpreting and adhering to this doctrine may compromise U.S. credibility and influence, and may require very expensive investments to build U.S. capacity to act unilaterally. Although the doctrine clearly lays out the reasons why preemption may be a desirable option, it offers little consideration of how preemption could negatively affect international law and institutions, the reputation of the U.S., and its force structure. Although rogue states, WMD, and terrorists do threaten the U.S., the nature and the immediacy of the threats they pose, and the best options for addressing those threats, should remain open to debate.


[1] President George W. Bush, The National Security Strategy of the United States of America, 20 September 2002.

[2] For an examination of these obstacles, see Betts, Richard K. 1982. Surprise Attack: Lessons for Defense Planning. Washington, DC: Brookings Institution.

[3] See Reiter, Dan. 1995. “Exploding The Powder Keg Myth: Preemptive Wars Almost Never Happen.” International Security 20(2):5-34.

[4] This assumes U.S. defense spending of roughly $450 billion, $380 billion in regular appropriations and $70 billion in emergency spending for the war in Iraq.

[5] See Betts, Richard K. “Striking First: A History of Thankfully Lost Opportunities.” Ethics and International Affairs 17(1).

[6] It is conceivable that the U.S. could wage a preventive war against a non-state group. In a sense, U.S. covert action to block radical political parties from coming to power could be considered preventive “war,” but in current policy discussions “preventive war” is used primarily to describe the use of military force against states.

[7] Viz. the ongoing controversies about political leaders’ influence on U.S. and British intelligence estimates of Iraq’s WMD programs.

[8] Glennon, Michael. 2003. “Why the Security Council Failed.” Foreign Affairs 82(3) March-June:16ff.

[9] Nevertheless, the risk of “copycat” preemptive action is probably low. As Michael Glennon argues, states will continue to make decisions on war and peace based on a careful evaluation of the economic and political costs and benefits, regardless of what an American document says about U.S. policy.

[10] Congressional Budget Office. “Letter to the Honorable Robert Byrd regarding the U.S. military's ability to sustain an occupation in Iraq.” 3 September 2003. Available at

[11] O’Hanlon, Michael. “Breaking the Army.” The Washington Post, 3 July 2003.