This article expands on a piece by the author, "Averting Catastrophe: Combating Iran's Nuclear Threat," which appeared in the Harvard International Review, volume 29 (2) (Summer 2007). Portions of that article are reprinted herein by permission of the Harvard International Review, which reserves all reprint rights to that article.
NO LEGAL DOCTRINE allows any nation to use force against an adversary that is developing nuclear weapons. The question for the international community is whether this prohibition has increased the risk of war. The United Nations Charter allows a nation to use force only if defending against an armed attack, regardless of the attack's destructive potential.1 Yet, the danger inherent in Iran's or North Korea's possession of nuclear weapons probably exceeds the risks associated with an armed attack by a nation with only conventional weapons, the greatest threat when the UN Charter was adopted in 1945. Under an expansive reading of the charter, a nation might use force to resist an adversary's imminent attack instead of having to wait until being attacked, but neither the charter nor any traditional provision in international law would allow the use of force against any nation planning or supporting a more distant nuclear attack, regardless of the nuclear attack's potential destructiveness and certainty.
As an alternative, a doctrine ofnuclear preemption could authorize force based on the danger a nation presents rather than on how soon that nation might attack. The new doctrine would recognize that nations involved in nuclear weapons development and the commission of grave crimes (aggression, crimes against humanity, genocide, or war crimes) are more dangerous than nations with conventional weapons planning imminent attacks or conducting attacks. Different from the murky concepts of preemption, prevention, and anticipatory self-defense, nuclear preemption would clarify under what circumstance, beyond self-defense, a nation can use force. It would provide a means to deter unstable leaders who intend to use nuclear weapons or transfer them to terrorists as soon as they possess them. A nuclear preemption doctrine would also cut down, paradoxically, on the number of instances in which force is used, for in the absence of such doctrine, countries have decided for themselves when it was right to use force-and they have not always done so legally. A clearly stated doctrine would not allow aggressive countries to manipulate the gray areas of current doctrines.
Modern Dangers and Traditional Law
When the UN Charter was adopted in 1945, only the United States possessed nuclear weapons. In 1953, the Soviet Union and the United States introduced thermonuclear weapons, hydrogen bombs, thus increasing significantly the devastation each nation could inflict. In 1957, they introduced intercontinental ballistic missiles. Self-defense under the charter-that is, a nation can use force to defend itself once an attack is imminent or has begun-perhaps still had relevance. A missile launched by either the Soviet Union or the United States might not reach its target for 18 to 30 minutes-enough time to begin a nuclear counterattack.2 In assessing the legality of nuclear weapons use, the UN's International Court of Justice issued an advisory opinion in 1996 indicating that a nation might be justified in using nuclear weapons in order to save itself.3 The court's decision seemed to ratify the Cold War doctrine of mutually assured destruction. A nation facing a devastating nuclear attack would be justified in responding with a defensive nuclear strike of its own before the adversary's first nuclear missile hit its target. Of course, the victim nation had to be able to launch before its adversary's missiles struck home.
In 1998, the usefulness of self-defense eroded when Pakistan announced it possessed nuclear weapons. With missile technology acquired from China and North Korea, Pakistan and India (which already possessed nuclear weapons), because of their close geographic proximity, were then capable of attacking each other-perhaps inflicting a first and decisive blow-before the other nation could respond witii defensive force. …