The Bush administration has announced a revolutionary change in U.S. military strategy: from Americas decades-old deterrence policy to a pre-emptive-strike scenario designed to neutralize hostile states and terrorist groups.

The Cold War defense mindset of Republican and Democrat presidents was summarized in two memorable phrases in the last century. One was flexible response. Under this strategy, sizable conventional forces were maintained in Europe to serve as a deterrent and to fight limited wars. It was thought by the Eisenhower administration to be a realistic alternative to the nuclear weapons no one believed could, or would, be used. President Kennedy modified it somewhat, hoping to deter all wars against the United States.

When the Soviet Union achieved nuclear parity with the United States, flexible response was replaced by what some regarded as the ultimate deterrent and others considered mad, hence its acronym, MAD, which stands for mutual assured destruction. MAD would keep the superpowers from fighting each other, because simultaneous annihilation would result in no winners. Whatever one thought of the morality of MAD, it did the job.

President Bush has said a new strategy is needed to deal with a new threat he believes is more dangerous in some ways to the United States than the threats posed during the Cold War. No one died from a nuclear exchange between the superpowers, but more than 3,000 Americans have died since the terror war against America began in the early 1980s, culminating in the Sept. 11 attacks last year.

The gist of the administrations rationale for pre-emptive measures is that in the war against terror, the old models of coalition building, consultation with allies and U.N. resolutions are no longer feasible or effective. In a 31-page document released Sept. 20, the administration says, While the United States will constantly strive to enlist the support of the international community, we will not hesitate to act alone, if necessary, to exercise our right of self-defense by acting pre-emptively against such terrorists. The new policy will also seek to deny terrorists sanctuary and support by convincing or compelling states to accept their sovereign responsibilities.

The document acknowledges the obvious: that nonproliferation efforts have failed and that states such as Iraq, North Korea and Iran have managed to obtain weapons of mass destruction. The administration now wants to shift the strategy from reacting to an attack to counterproliferation, saying, We must deter and defend against the threat before it is unleashed.

Coupled with an even stronger defense designed to keep Americas enemies from even thinking about an attack (but ignoring that the religious fervor behind many of these threats may be immune to any deterrence short of pre-emptive assassination), the administration pledges efforts to ignite a new era of economic growth through free markets and free trade. The idea here is that if Americas enemies have more food on their plates, they are less likely to attack us.

The new strategy is based on a moral premise. It is that America is a good nation that can be expected to act out of pure motives and in the interest not only of its own people but of free people and those yearning to breathe free everywhere. This will seem arrogant and self-righteous to some, but it is the only strategy that has a chance of putting America first, which is the primary responsibility of any president.

No nation, and certainly not the United Nations, will care more about America or American interests than America will. A free and safe United States is in a better position to lead the world with its values and virtues than one that is economically crippled and insecure.

No American administration has articulated a sound defense policy since the collapse of the Soviet Union more than a decade ago. The Bush administration has now done so, and it is a good one. Now comes the difficult part how to enact it.