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The Implications of Preemptive and Preventive War Doctrines: A Reconsideration

Authored by Dr. Colin S. Gray. | July 2007

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Preemption has been, and remains, a leading concept of this decade. But despite its ubiquity in public discourse and its policy relevance, it is a source of great confusion. The term is misused, in some cases deliberately one suspects, but it must be admitted that strategic theorists have offered very little worthwhile reading on the subject. This monograph clarifies the meaning of preemption and distinguishes it from prevention and precaution. It critically reviews the principal charges levelled against preventive warfare and uses that analysis to provide at least the bare bones of strategic theory, more strictly of an alternative to theory relevant to such warfare. The analysis concludes with a set of policy and strategy relevant implications for the United States.

Preemption is not controversial; legally, morally, or strategically. To preempt means to strike first (or attempt to do so) in the face of an attack that is either already underway or is very credibly imminent. The decision for war has been taken by the enemy. The victim or target state can try to disrupt the unfolding assault, or may elect to receive the attack before reacting. In truth, military preemption will not always be feasible.

By way of the sharpest contrast, a preventive war is a war of discretion. It differs from preemptive war both in its timing and in its motivation. The preemptor has no choice other than to strike back rapidly; it will probably be too late even to surrender. The preventor, however, chooses to wage war, at least to launch military action, because of its fears for the future should it fail to act now. In other words, the preventor strikes in order to prevent a predicted enemy from changing the balance of power or otherwise behaving in a manner that the preventor would judge to be intolerable. Naturally, the more distant the anticipated menace, the greater the degree of guesswork as to the severity and timing of the danger. A precautionary war is one waged not out of strong conviction that a dangerous threat is brewing in the target state, but rather because it is suspected that such a threat might one day emerge, and it is better to be safe than sorry.

Put in the vernacular, preventive war, the real subject of this monograph, refers to the option of shooting on suspicion. In an age of weapons of mass destruction (WMD), it could be too late to shoot if one waits for suspicion to be verified by hostile behavior. The official American attitude toward preemption has fluctuated between the admirable declarations of principle by two of its outstanding lawyers: Daniel Webster in 1842 and Elihu Root in 1914. Webster insisted that preemptive action is justified only in the event of a threat that is so imminent that there is no time for other measures. Root took the far more expansive and flexible view that preemptive action must be permitted on a timeline that allows the victim state to take precautions. In effect, Root amended Webster by claiming the legality of a decision to wage preventive war in order to forestall the maturation of the menace. This is not preemption, it is prevention.

Contrary to the impression one might derive from the scale and intensity of the legal debate, it happens to be the case that there really is no legal issue about this subject. International law, in the form of the United Nations Charter, recognizes the inherent right of self-defense by states, and it does not oblige a victim state to wait passively to be struck by an aggressor, although it appears to do so—it is a matter of interpretation. In short, preventive action by way of anticipatory self-defense is legal, or legal enough. Understandably, this permissive interpretation of the license granted by the right of self-defense is open to criticism. In effect, it means that there is no legal constraint on a state's right to resort to force.

The author explains that prevention has not only been a common motive for war, actually it has been quite routine. It is difficult to find historical cases of warfare wherein prevention was not a motivator. Wars typically occur for several, even many, reasons. Prevention is nearly always prominent in the cluster of those reasons. The concept of preventive war has an ominous ring to it that is not entirely deserved. Poor historical understanding is the explanation.

In this monograph, the major criticisms and issues bearing upon preventive war are presented, and their merits and demerits are highlighted. Preventive war is charged with being an act of aggression that is illegal and immoral. We find no value in this accusation, at least as a generality. Preventive war is claimed to be feasible only if intelligence is immaculate. Again, we are unimpressed. It is the view of the author that, with a few exceptions, intelligence needs only to be ";good enough." To demand perfect knowledge is to prohibit preventive action. The charge that prevention is seen by some people as a panacea, a ";silver bullet," is found to have merit. Next, the claim that preventive warfare must be considered in a framework of probable and possible costs, as well as expected benefits, is approved strongly; it is all too easy to allow one's wishes to suppress suggestions of negative possibilities. Preventive war is charged with prejudging the failure of other policy instruments. This is true, but not conclusively so. Very often, arguments for more time for diplomacy, sanctions, political subversion, and so forth, are really efforts intended to stall a move to military action, rather than serious claims for prospective success. We need to beware of excuses for endless delay regarding the military option. It is claimed that preventive action sets a most undesirable, even dangerous precedent. This may be true, though it is almost certainly exaggerated, since states scarcely need foreign examples to license muscular self-defensive behavior. To the degree to which it is true, one has to respond by acknowledging the probable fact, while not allowing it to serve as a veto on action we deem essential. Finally, it is fairly popular to argue that a policy that favors prevention represents a futile quest for absolute security. This is a very weak argument. To be willing to act preventively need not be an expression of a foolish search for total security. The argument depends upon a glaring non sequitor.

The monograph offers some thoughts and suggestions with respect to prevention and strategic theory. It observes that there is extant no theory of preventive war. Two reasons for this are postulated. First, the concept is political, and therefore escaped the attention of the rational choice analysts who constructed their narrowly military strategic theory in the 1950s and 1960s. Second, preventive war is not a concept akin to deterrence and containment, despite the suggestion to the contrary made by President George W. Bush. Preventive action is regarded in this monograph as an option that very occasionally is necessary. It does not have the character of a reasonably reliable default strategy, as do deterrence and containment. The following are the principal observations and suggestions for improving theoretical understanding of preventive war: Preventive war is simply war, distinguished only by its timing.

  1. Since preventive war is simply war, it is already explained adequately by Clausewitz.
  2. Preventive war, in common with all war, is a gamble.
  3. The ";preventor" begins with the advantage of the initiative, but if success is not achieved swiftly and decisively, that advantage will rapidly diminish as the enemy recovers and counterattacks.
  4. The assessment of a preventive war option has to be on the basis of cost-benefit analysis (or guesswork).
  5. The anticipation of high costs to prevention action need not be a showstopper. It depends upon the value of the stakes.

By way of conclusions, the monograph identifies some key implications for U.S. policy and strategy. These are drawn from the whole body of the enquiry and, admittedly, contain a few controversial items.

  1. Preemption is not controversial.
  2. To wage a preventive war requires the fortitude to withstand a great deal of criticism, foreign and domestic. As the principal guardian of international order, the United States needs to be willing to brave that criticism and proceed to do what it believes needs doing.
  3. The United States does not need, and should not talk as if it has, an explicit doctrine of prevention (not even when it is thinly disguised as preemption).
  4. The United States needs to think politically about its resort to force and be prepared to use military power for political purposes.
  5. Preventive war requires very good, but not perfect, intelligence. Of course, it has to be good enough to serve as a guide to action, but a demand for immaculate intelligence could rarely, if ever, be met. It would function as a needless showstopper.
  6. Preventive war is not, and cannot be, a doctrine, no matter what officials claim to the contrary.
  7. To choose the preventive war option is to gamble on military success, but to be well-justified in retrospect that success will not necessarily need to be 100 percent.
  8. Preventive action, for choice, should take the form of a raid, not an invasion and occupation. The United States should not aspire forcibly to remodel alien societies and cultures. The issue is not one of desirability, but rather feasibility.

The principal criteria for preventive action comprise the following:

  • Force must be the last resort, not temporally, but with reference to the expected failure of other policy instruments.
  • The condition to be prevented by force has to be judged too dangerous to tolerate.
  • The benefits of preventive military action must be expected to be far greater than the costs.
  • There has to be a high probability of military success.
  • There should be some multinational support, the more the better. But, the absence of such support should not be allowed politically to function as a veto on actions.