Thanks to the Sept. 11 interview of Sarah Palin by Charles Gibson of ABC News, the Bush Doctrine has become part of the American vocabulary. Although it has been a fateful doctrine - it was used to justify the attack on Iraq - many Americans reported that they were as clueless about it as Gov. Palin. So what is the Bush Doctrine? According to international law as generally understood since the creation of the United Nations, a pre-emptive attack is legal only if a country has certain knowledge that an attack on it is imminent - too imminent for the matter to be taken to the U.N. Security Council. Pre-emptive war is different from preventive war, in which a country, fearing that another country may become strong enough to threaten it at some time in the future, attacks it to prevent this possibility. Preventive wars are illegal under international law. This distinction, however, creates a terminological problem: Although preventive war is worse than pre-emptive war, to most ears preemption sounds worse. Many people, therefore, speak of pre-emptive war when they mean preventive war. To avoid confusion, we can use the term pre-emptive-preventive war. Neoconservatives, the most powerful of whom is Vice President Dick Cheney, had long disliked the idea that America's use of military power could be constrained by the prohibition against preemptive-preventive war. In 1992, his last year as secretary of defense, Cheney produced a draft of the Defense Planning Guidance that said the United States should use force to pre-empt" and "preclude threats." After the 9/11 terrorist attacks, the neocons were able to turn their wish into U.S. policy.