Ackerman refutes his own thesis most clearly when he harkens back to the Nazi “war of aggression,” the chief charge against the criminals at Nuremberg. He implies an analogy between preemptive strikes and the “war of aggression” that the allied victors insisted on criminalizing, as if that makes his case against preemption stronger. That is an astounding argument given the circumstances that led to World War II. By the time the war ended, everyone was pretty well convinced that the West’s failure to preempt Hitler’s various nonviolent preparations for war had left all Europe defenseless before the Nazi onslaught.

The idea that World War II argues for restricting the right of anticipatory self-defense is preposterous. On the contrary. Britain and France should have gone to war over the remilitarization of the Rhineland in 1934, to make no mention of the later Anschluss with Austria, or — most disastrous of all — the occupation of Czechoslovakia. In each case, a military response on the part of Britain and France was not merely justified, but urgently necessary. Yet, according to Ackerman’s “rule,” the British or French countermoves in each case would have been illegal.

This absurd position unfortunately finds a strong foundation in the actual text of the U.N. Charter. That is because, according to a strict reading, the U.N. Charter outlaws virtually all uses of force, no matter how necessary, unless the Security Council approves or an “armed attack occurs.” Article 2(4) prohibits “the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the Purposes of the United Nations.”