The Use of Force in Afghanistan and Iraq

Abstract

Michael Walzer defines preventive wars as attacks “that respond to a distant danger, a matter of foresight and choice”² while preemptive wars as those that respond to an actual threat that has been issued.³ What distinguishes preemption from prevention is the prevalence of a “sufficient threat,” which in Walzer’s words comprises “a manifest desire to injure, a degree of active preparation that makes that intent a positive danger, and a general situation in which waiting or doing anything other than fighting greatly magnifies the risk.”⁴ Prevention differs from preemption, both in terms of timing and motivation.

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.¹