The bombs have started falling and the world is once again at war. While the adversary is the same -- the regime in Baghdad -- and the terrain familiar, this conflict is much different from the first clash between Iraqi President Saddam Hussein and the international coalition led by the United States 12 years ago. In this war, as in the first one, the result is almost certain to be the same: a victory for the West. Yet the collateral damage will be much greater. Rather than heralding the birth of a new world order, the second Persian Gulf War may well mark the beginning of an era of uncertainty and disorder.

The official countdown to war began earlier this week when U.S. President George W. Bush gave Mr. Hussein 48 hours to step down, but the roots of the conflict were sown over a decade ago. In the aftermath of defeat in the first Persian Gulf War, Iraq agreed to United Nations resolutions requiring total disarmament as a condition of peace. Those agreements were mostly honored in the breach. Shamefully, however, the world chose to ignore those violations, and Mr. Hussein gladly pocketed the opportunity to rebuild his arsenals.

Even the U.S. was complicit in this arrangement, but the terrorist attacks of Sept. 11, 2001, changed the American strategic calculus. Candidate Bush excoriated his predecessor's foreign policy for its arrogance and inability to focus on U.S. national interests; President Bush has awakened to new threats and declared a doctrine of preemption in which the U.S. would move against enemies rather than let them strike first. Iraq, with its history of attempts to build arsenals of weapons of mass destruction, its use of such weapons against its own citizens, and its record of aggression against its neighbors, was deemed a clear and present danger demanding a response.