3 JANUARY 2005



            The concept of preemption in its modern application, notably the United States’ National Security Strategy of 2002 and recent discourse surrounding US interventions, is markedly expanded from its original meaning.  The definition that originated with Daniel Webster, Secretary of State under William Henry Harrison and John Tyler, and was adapted by just war scholars such as Michael Walzer, is actually relatively lucid, presenting little moral dilemma in its proper application.  Richard Betts writing for the Brookings Institute explains, “Preemption is unobjectionable in principle, since it is only an act of anticipatory self-defense in a war effectively initiated by the enemy…Beating the enemy to the draw by striking before he launches his attack is reactive, even if it involves firing the first shot.”[1]  The problem lies in the misapplication and evolving definition of preemption and the implications that has on how war is conducted.  Preemption has been increasingly defined as preventive in nature and, as it has been used to justify modern conflicts, no longer adheres to the criteria that initially distinguished it as a just form of intervention.  This evolution in policy and definition raises a number of independent issues.  Primarily, there is inherent danger in redefining preemption such that it begins to go outside of the bounds of accepted just war theory and international law.  This misconstrues how conflicts are portrayed using the assumptions that accompany the idea of preemption, and it threatens an unjust intervention under the auspices of justice.  While preemption properly defined is widely acknowledged as a just form of intervention, the second issue raised is whether or not there is a case to be made for interventionist policies that do not fall under preemption.[2]  Are there types of preventive action that are morally justified given the changing world dynamic?

            The concept of preemption, defined as such, can be originally traced back to Daniel Webster who said it was justly applied to situations in which there existed an “instant [and] overwhelming” threat of aggression.[3]  This definition has since been modified by scholars such as Michael Walzer, professor of Social Science at the Institute of Advanced Study at Princeton University, to mean anticipatory attack against adversaries who present sufficient threat to a state’s political independence or territorial integrity.  Walzer’s definition is widely acknowledged as the accepted just war definition of preemption but even as he discusses in his book, Just and Unjust Wars, it is vague.[4]  Offering more specificity, Neta Crawford, associate professor of Brown University’s Watson Institute for International Studies, outlines four criteria that define just preemption.  Primarily, the state actor considering preemption must have a narrowly defined concept of “self”. “When security is defined in terms broader than protecting the near-term integrity of national sovereignty and borders, the distinction between offense and defense blurs hopelessly.”[5]  A well-defined concept of self and self-interest means that attack will not be justified for non-vital aspects of statehood such as short-term economic prosperity, but reserved for the political independence and territorial integrity of which Walzer speaks in his definition of preemption.  Second, Crawford says that there must be a justified fear of imminent attack and that aggressive intent as well as the capacity to do immediate harm is present.  Third, preemption must be likely to succeed and, finally, military force must be required as all other options are exhausted, impossible, or unreasonable under the circumstances.[6]  For the purpose of this discussion of preemption, I will use Crawford’s criteria as the framework definition of preemption by which competing interpretations can be measured.  There are various reasons to prefer this interpretation.  It is the most specific and encompasses the main sources of expertise on the subject while extending upon them.  Second, it has the clearest articulation of the role preemption plays in self-defense by stipulating that there must be a clear articulation of self-interest before a state can justly launch a preemptive attack.  Finally, it cleanly balances the rights of a nation-state to its sovereignty and territorial integrity while checking any unjust anticipatory actions on perceived aggressors.

            Anticipatory acts that fail to satisfy any of the above conditions can then be seen as preventive.  This is because failure to satisfy any of the above tenets means that a state is no longer preempting an inevitable act of aggression but rather working to prevent against its possibility.  A product of 17th century Europe, preventive war was historically intended to maintain the balance of power between states and justified military action to support that end.  The only justification preventive war required was “malign intentions” and thus it was often seen as naked aggression.[7]  Today, as the United States lives out its unipolar moment, acts of this type of military balancing and their prevention are obsolete as is the defense posture the United States held during the bipolar world of the Cold War era.  The threat now faced by the United States comes from “new deadly challenges…from rogue states and terrorists,” according to the 2002 National Security Strategy of the United States (NSS).  The unique nature of these threats make deterrence a largely ineffective measure as these enemies are willing to risk more and have less to lose.  They also present the United States with more immediate threats since terrorists and rogue nations can operate in relative secrecy and have massive potential for destruction at costs far less to initiate than to defend against.[8] 

            Some feel, including the Bush administration, that the only method of defending against these types of dangers lies in a preemptive defense policy.  In a speech given for the American Enterprise Institute for Public Policy Research, Charles Krauthammer discusses the option of preemption as “especially necessary” given the underrable nature of terrorists and the element of surprise they present.[9]  Preemption according to those who advocate this method of foreign policy, however, is not the same preemption that Webster established or of which Crawford speaks.  It is actually preventive in nature.  Krauthammer goes on to say: “the point of preemption is to deter the very acquisition of WMDs in the first place.”  This idea of attacking in order to prevent a potential aggressor from gaining the capability to harm the United States is not preemptive but preventive, using “malign intentions” as a justification for attack without the need for substantiated proof of capability, imminent threat, or the requirement of military force to avert disaster.   This sentiment is further reflected in the NSS when it states that the United States must be able to “stop rogue states and their terrorist clients before they are able to threaten or use weapons of mass destruction.”[10] This misinterpretation blurs the already fine line between preemption and prevention, which presents a number of independent harms to American foreign policy and its coalescence with the international community. 

            Primarily, an expanded definition of preemption fails to protect against any of the harms that have made preventive attack an unfavorable option in the eyes of the international community as reflected by the UN Charter, Article 51, which only recognizes a nation’s “inherent right” to self-defense against armed attack.[11]  Not only a justification for blatant aggression, preventive war creates an international environment of fear, as well as nation-states, and increasingly terrorists, more likely to display increased aggression in response.  Furthermore, given that preventive war, unlike preemption, does not necessarily require knowledge of the time and place of enemy attack nor a clear concept of exactly who the enemy is, it can make the distinction between combatants and non-combatants difficult.[12]  Preemption also requires a specific understanding of what constitutes self-interest.  Without this, nearly all preventive acts could be justified as self-defense when any of a number of non-essential aspects of statehood are threatened, making war an easy recourse.  Justifying preventive acts as morally permissible preemptive actions also makes the consideration of non-military options less likely given the usually higher success rate and greater efficiency of military strikes—why negotiate with a potential enemy if you can eliminate it altogether, achieving greater security with less risk of attack.  Pragmatically, there may be no reason to do so.  However, morally, the sanctity of human life and the inherent right of nations to their political independence and territorial integrity obligates any nation considering preventive acts to also consider their moral implications.

            Second, an expanded definition of preemption, as advocated by the NSS and Krauthammer, eliminates crucial criteria that have established preemption as a just form of anticipatory action.  The legacy that created just war theory carries with it the weight of hundreds of years of legal, philosophical and religious contemplation on the subject of war and how to reconcile its brutality with that within man that desires peace and security.  Thus, any reference to that tradition when discussing modern war and conflict also carries with it the weight of just war legacy.  To expand the definition further and to allow leniency in its meaning would create a defense dynamic that Webster’s definition attempts to prevent—defense based on suspicion, not intention of hostile action.  Just war theory draws a natural divide between moral consideration in war and the realist approach to preventative wars as “normal, even common, tools of statecraft…”[13]  To use the one as a disguise to make the other acceptable is to abuse the natural intent of just preemption and to begin a gradual process of rendering it void of true meaning.

            The NSS attempts to revise the concept of preemption in a way that allows for US foreign policy to slide over the already vague line between preemption and prevention.  The National Security Strategy states: “[W]e must adapt the concept of imminent threat to the capabilities and objectives of today’s adversaries… taking anticipatory action to defend ourselves, even if uncertainty remains as to the time and place of the enemy’s attack.”[14]  The danger in this stance is that it makes the definition of imminent threat infinitely regressive.  If a threat can be assumed imminent because no evidence exists to prove it otherwise, the potential aggressor becomes guilty and punishable by default—the reverse logic of all American jurisprudence, which assumes innocence until guilt is proven.  This would allow the United States to attack nearly anywhere in the world with relatively unsubstantiated claims of emerging threats.  This is the danger of preventive actions: they can easily slip into justification of naked aggression.  However, it may also be unreasonable to expect the United States or any other nation who faces these unique threats to give all adversaries the benefit of assumed innocence until all the conditions of just preemption are met.  In an article in International Security, Dan Reiter refers to three instances that constitute the only cases of true preemption in modern history: World War I, the Chinese intervention in Korea, and the Six Day War of 1967.[15]  Thus, the increasingly relevant question is raised as to whether or not such a thing as just prevention exists—a stance that has been rejected historically in just war theory, but for which a strong case can be made given the nature of the enemies the world now faces.

            While it is possible that there may be a case for just prevention, it is valuable to understand the need to syntactically distinguish preemption from prevention.  The justification for preemption, if it adheres to Crawford’s or Webster’s definitions, is clear and invariably persuasive as a moral act of self-defense available as an option to any country.  This justification can only be retained if the integrity of these definitions is maintained.  Thus, preemption should remain a distinct category of anticipatory actions available to a country.  Given that there may also be a case for just prevention, the objective is now to determine the circumstances under which prevention is justified, and where the line lies that would distinguish just prevention from unjust prevention.

            The three cases that distinguish themselves are the threats that emerge from terrorists, rouge nations, and countries that harbor terrorists.  Most other threats a nation can defend itself against by adhering strictly to preemptive measures or other modes of defense and negotiation.  In the case of terrorism, terrorist networks who have recently engaged in specifically known terrorist activities are not protected by just war theory as they have taken part in explicitly criminal activities, thus strike is legitimized at any time as long as it is winnable and proportional.  When a terrorist group is known to exist but is idle, the rules for just anticipation do apply.  This would be considered just prevention as the concept of “imminence” becomes nearly impossible to establish given a world in which terrorists operate by surprise and can strike at any place, at any time.  While defensive measures can play some role in deterring this, the rise of the suicide bomber further exacerbates the problem.  A nation should have the right to provide itself with some level of defense without having to overcome the sometimes impossible task of proving that an inevitable attack is coming in days or weeks.  However, there must exist some check as “paranoid aggression promises endless war.”[16]  In order to justify a preventive attack against terrorist networks, all that should have to be established is that there is aggressive intent and that the capacity exists to do harm.  As Walzer discusses, “Randomness is the crucial feature of terrorist activity.”[17]  A state should not have to prove that the attack is inevitable or necessarily immediate before it can justify actions of self-defense so long as they are proportional and likely to succeed. 

            The second issue lies with rogue nations.  Michael Klare, professor of Peace and World Security Studies in Massachusetts’ Five College Program, defines rogue nations as states “of the Third World…said to threaten US interests because of their large and relatively modern militaries, their pursuit of WMD, and their hostile stance toward the United States and its allies.”[18]  The proliferating presence of weapons of mass destruction (WMDs) in the world, while dangerous generally only becomes a true threat when acquired by rogue nations more willing to take risks and sacrifice the welfare of their people for the gamble of power backed by the threat of nuclear annihilation.  Preventive war is justified where a capability to launch nuclear weapons is imminent within days or weeks, not necessarily intelligence that a strike is coming.  This must also be accompanied with blatantly aggressive intent and there must be a clear case that military force is necessary and that diplomatic measures have been exhausted and failed.  Given the greater magnitude and lower predictability of the threat these types of nations present, a state considering anticipatory action should have the right to take preventive action.  The danger of constricting a nation to preemptive action in this case lies in the fact that proof of imminent threat might come too late to prevent the impact of a nuclear confrontation.  These nations tend to be closed off and relatively secretive about their activities so proof of imminent threat becomes even more difficult to substantiate.  Also, allowing for a rogue nation to gain nuclear capability after warnings of aggressive intent always places a nation considering anticipatory action in a catastrophically dangerous position.  For a rogue nation that has already acquired these capabilities, all that is needed to justify anticipatory action is explicitly aggressive intent and only after all non-military options have been exhausted.

            The third threat comes from nations who harbor terrorists.  The NSS states: “We make no distinction between terrorists and those who knowingly harbor or provide aid to them.”[19]  While this may seem justified given the defense of preventive action against terrorists above, the Security Strategy’s stance that no distinction is to be made is actually the type of “paranoid aggression” of which Crawford speaks.[20]  A distinction is necessary because while terrorists do not have any claims to political independence or territorial integrity, nations do.  While terrorists forfeit many of their rights at the point at which they endanger and kill innocent civilians, nations who harbor them must be evaluated differently.  Primarily, a nation must be supporting them knowingly and maliciously, they must be fully cognizant of the role they have in supporting whatever terrorists may reside within their borders or to whom they are providing aid.  Secondly, they must be a main source of livelihood for the terrorists and it must be sanctioned by the government itself, not from those loosely connected with, but not a part of, the government.  If the nation plays a small role in the terrorist organization’s livelihood and only provides an inconsequential amount of aid or sanctuary, anticipatory actions are not warranted.  However, if the nation is the lifeblood of a terrorist organization, if diplomatic efforts have been exhausted for it to relinquish that aid, and if there is justified fear that the terrorists who rely upon it are a realistic threat, preventive attack on the nation is warranted even though the nation itself does not present a imminent threat to the anticipating nation’s self-defense. 

            Though the NSS is correct in stating that the concept of imminent threat must be adapted to modern adversaries, it does not delineate any standard for a new concept of imminent threat.  The dilemma that has occurred as a result is that there is no existing standard to which the administration can be held by the American people or the international community.  A second problem that has occurred is that, as a result of the misapplication of preemption to fit the need for a new definition of imminent threat, the concept has lost a great deal of its legitimacy as a just form of anticipatory action.  The solution to both these problems is two fold: primarily, there must be a clear, lucid definition of preemption that is distinct and categorically independent of preventive acts.  Second, the concept of just prevention must be explored as a means by which a nation can defend itself legitimately in the case that preemption is inadequate to maintain a reasonable level of self-defense against modern aggressors.  While just war theory has discussed both subjects, it must specifically adapt itself to these specific issues.  This paper is one proposal for both solutions.  The underlying aim, however, is to bring to light the importance of the distinction itself.  If a clear concept of preemption is maintained and the conditions that must be met to legitimize it are clear, it will carry with it the potent ideas of justice in self-defense and moderation and clear-headedness in war every time it is invoked.  The danger that is identified here is that without a clear definition of preemption and what gives it legitimacy, the door is opened for the justification of unjust actions by way of a blurred idea of what is acceptable anticipatory action and what is not.  If that clear definition does not exist, the idea of preemption will be void of meaning in the context of justice in war and legitimate cause.  Clearly defined, preemptive action is not morally problematic but, in fact, always a moral recourse if specific criteria are present.  Furthermore, there are instances in the modern world of threats that fall outside preemption and justify preventive anticipatory action, specifically the threats of terrorism and rouge nations.  A clear definition dividing just prevention and unjust prevention is also necessary to ensure that a clear idea of just anticipatory actions is maintained.  For fairness and justice in war to be upheld, this clarity is essential.  Defining just preemption and just prevention is one such clarification to ensure that legitimacy is maintained.




Betts, Richard. “Striking First: A History of Thankfully Lost Opportunities.”  Ethics and International Affairs 17, no 1 (2003): 1-4.


-------, Surprise Attack: Lessons for Defense Planning.  Wasington D.C.: Brookings Institution, 1982.


Charter of the United Nations, Article 51.  New York: United Nations, 1945.


Crawford Neta C.  “The Best Defense: The problem with Bush’s “preemptive” war doctrine.”  Boston Review (2002).


Klare, Michael.  “The Rise and Fall of the “Rogue Doctrine”: The Pentagon’s Quest for a Post-Cold War Military Strategy.”  Middle East Report, no 208 (1998).


Krauthammer, Charles.  “An American Foreign Policy for a Unipolar World.” 2004 Irving Kristol Lecture.  Washington D.C.: AEI Annual Dinner, 2004.


Levy, Jack S.  “Declining Power and the Preventive Motivation for War.”  World Politics 40, no 1 (1987).


National Security Strategy of the United States of America.  Washington D.C.: The White House, 2002.


Reiter, Dan.  “Exploding the Powder Keg Myth: Preemptive Wars Almost Never Happen.”  International Security 20 (1995): 5-34.


Silverstone, Scott.  Discussion with Dr. Silverstone, assistant Professor, USMA, regarding preventive and preemptive war.  October 2004.


Walzer, Michael.  Just and Unjust Wars.  New York: Basic Books, 2000.


Worley, Robert D.  “Waging Ancient War: Limits on Preemptive Force.”  Strategic Studies Institute, US Army War College, (2003).




[1] Richard Betts. “Striking First: A History of Thankfully Lost Opportunities.”  Ethics and International Affairs 17, no 1 (2003): 1.

[2] Dr. Scott Silverstone.  Discussion with Dr. Silverstone, assistant Professor, USMA, regarding preventive and preemptive war.  October 2004.

[3] Michael WalzerJust and Unjust Wars.  (New York: Basic Books, 2000): 74.

[4] Ibid, 85.

[5] Richard K. Betts. Surprise Attack: Lessons for Defense Planning (Wasington D.C.: Brookings Institution, 1982): pp.14-43.

[6] Neta C. Crawford.  “The Best Defense: The problem with Bush’s “preemptive” war doctrine.”  Boston Review (February/March 2002): 4-5.

[7] Robert D. Worley.  “Waging Ancient War: Limits on Preemptive Force.”  Strategic Studies Institute, US Army War College, (2003): 20.

[8] National Security Strategy of the United States of America. (Washington, D.C.: The White House, 2002): 14-15.

[9] Charles Krauthammer.  “An American Foreign Policy for a Unipolar World.” 2004 Irving Kristol Lecture.  (Washington D.C.: AEI Annual Dinner, 2004).

[10] NSS, 14.

[11] Charter of the United Nations, Chapter 7, Article 51.  (New York: United Nations, 1945).

[12] Crawford, 9.

[13] Jack S. Levy.  “Declining Power and the Preventive Motivation for War.”  World Politics 40, no 1 (1987): 84.

[14] NSS, 15.

[15] Dan Reiter.  “Exploding the Powder Keg Myth: Preemptive Wars Almost Never Happen.”  International Security 20 (Fall 1995): 5-34.

[16] Crawford, 5.

[17] Walzer, 197.

[18] Michael Klare.  “The Rise and Fall of the “Rogue Doctrine”: The Pentagon’s Quest for a Post-Cold War Military Strategy.”  Middle East Report, no 208 (1998): 12.

[19] NSS, 5.

[20] Crawford, 5.