Now that the war has begun, the world hopes it will end swiftly with minimal casualties. But wars are almost always unpredictable. As U.S. President George W. Bush himself has warned, the conflict could be "longer and more difficult than some predict." There is also the possibility that, even if it ends swiftly, the threat of global terrorism will not go away. Military victory does not necessarily make the world safer.

This war is essentially different from past wars. It is a war to prevent the spread of weapons of mass destruction and international terrorism. It is a war aimed at toppling a dangerous dictatorship -- the regime of Iraqi President Saddam Hussein -- and spreading democracy throughout the Middle East. And it is the first war in history to implement the doctrine of preemption. President Bush said American and coalition forces are fighting to "disarm Iraq, to free its people and defend the world from grave danger."

The problem is that this war has no explicit U.N. authorization. In the 1991 Persian Gulf War, the United States led a U.N.-backed multinational force. This time around it has the support of more than 35 nations, including Japan, but not its traditional European allies like France and Germany. There is now a deep sense of mistrust between the U.S. and Western Europe.