You remember, of course, the Caroline incident? (Don't worry; neither did I.) In 1837 Canadian forces attacked a U.S. ship of that name, killed one of its passengers, set it on fire and then cast it adrift just above Niagara Falls. The British government said its forces had acted in self-defense; those on the Caroline, London claimed, were supporters of a rebellion against British rule in Canada. In an exchange of diplomatic notes, U.S. Secretary of State Daniel Webster argued that a nation could only justify such pre-emptive hostile action if there was a necessity "instant, overwhelming, leaving no choice of means and no moment for deliberation." Ever since, Webster's dictum has been regarded as a principle of international law.
I found myself reading up on the Caroline after a trip to London last week. In Britain commentators and policy makers are agog about a new U.S. doctrine, unveiled by President George W. Bush in a commencement address early this month at West Point. Surveying the post-Sept. 11 world, Bush said that "if we wait for threats to fully materialize, we will have waited too long...We must take the battle to the enemy, disrupt his plans and confront the worst threats before they emerge." The speech, wrote Peter Riddell, a sober columnist for the London Times, "signaled the most far-reaching shift in American foreign policy for more than 50 years."
Is that the case? At first sight, Bush's doctrine of pre-emptive attack seems frightening. True, Administration officials have said that pre-emption can take nonmilitary forms. But it still seems as if the U.S. has arrogated to itself the right to go to war whenever it sniffs danger from a regime it doesn't like. And Bush's speech seems inconsistent both with the very narrow Caroline principle and with Article 51 of the United Nations charter, which allows self-defense only "if an armed attack occurs" (not "is likely to occur") against a nation. Yet pre-emptive strikes can often be justified even if they don't meet the letter of the law. At the start of the Six-Day War in 1967, Israel, fearing that Egypt was aiming to destroy the Jewish state, devastated Egypt's air force before its pilots had scrambled their jets. In 1981 Israel bombed the Osirak nuclear reactor in Iraq, an incident that provoked worldwide disapproval. But given what we now know about Saddam Hussein's regime, only the most nit picking of lawyers--admittedly, a large category--would still condemn the action.
In a similar way, pre-emption can be justified by the nature of today's threats. The only way to challenge the enormous strength of the American armed forces is with unconventional warfare--terrorism or the use of weapons of mass destruction. The U.S. edge in tanks and warplanes counts for nothing against such threats, so other methods need to be found. Moreover, some serious dangers come not from national armed forces but from groups like al-Qaeda, against which conventional doctrines won't work. How are we supposed to deter Osama bin Laden when we can't find him?