President Bush used three main arguments to justify sending American troops into Iraq. The first tied Saddam Hussein to Al Qaeda, but the evidence that was presented publicly remained thin. Public opinion polls show that many Americans accepted the administration's word on the connection, but overseas responses were more skeptical.
The second argument was that replacing Saddam Hussein with a democratic regime was a way to transform the politics of the Middle East.
A number of neo-conservative members of the administration had urged this before taking office but were unable to turn it into policy during the first eight months of the administration.
After Sept. 11, however, they quickly moved through the window of opportunity (even though North Korea posed a more imminent danger). President Bush spoke often of regime change.
The plausibility of this argument was debated at home and abroad, and the merits probably lie somewhere between the proponents and skeptics.
Our dedication to the broad values of democracy and human rights is part of our ''soft'' or attractive power and an essential part of our foreign policy.
But democracy is a fragile plant that requires carefully cultivated soil. It is not easily transplanted. Of the places where the United States has sent troops in the last half-century, only a minority of the interventions resulted in democratic governments.
Optimists cite the role of American military occupation in the democratization of Germany and Japan after World War II.
But conditions in the Middle East today are not like Germany and Japan in 1945. Both of those countries had large middle classes, prior experience with democracy, and a prolonged and largely unopposed American military presence.
Given its history and internal divisions, postwar Iraq is unlikely to look like democracy as we know it, but it will be a better and more pluralistic regime than now exists.
American military success may lead Iran and Syria to temper their policies, but if President Bush is unable to persuade Israeli Prime Minister Ariel Sharon to reach a compromise acceptable to the Palestinians, the map of the region may change less dramatically than the optimists hope.
The third argument was the clearest and most widely accepted. It focused on preventing Saddam Hussein from possessing weapons of mass destruction.
Most countries agreed that Saddam had defied UN Security Council resolutions for a dozen years.
Moreover, Resolution 1441 unanimously put the burden of proof on him to demonstrate what had happened to weapons that UN inspectors had been concerned about before they left Iraq in 1998.
If President Bush had focused on this third argument and been willing to work out a compromise along the lines suggested by Canada, he could have built a far broader coalition for the war (Canada, and later Britain, suggested an agreement to give the UN inspectors more time in return for clear benchmarks and a date certain to declare the end of the process.)
I believe France might have gone along, but even if it had used its veto, American actions would have been legitimized by a majority in the Security Council similar to that we enjoyed when we intervened in Kosovo in 1999.
Unfortunately, the administration sent mixed messages. The more the unilateralists in the administration talked about regime change and going ahead no matter what the UN did, the more other countries became convinced we were not serious about cooperation, and the more the issue became the legitimacy of American power rather than the transgressions of Saddam Hussein.
The result is the right war at the wrong time, but the point is now moot.
Those of us who are critical of the clumsy handling and timing of the war must admit that indefinite containment was unlikely to succeed.
Saddam Hussein had a record of taking high risks, a clear intention to develop weapons of mass destruction, and a proven willingness to use them.
Enforcing Security Council Resolutions 687 and 1441 is better than returning to the evasive politics of the 1990s when Saddam Hussein successfully defied a divided United Nations.
We multilateralists must now hope that the war is brief, that the Iraqi people will visibly welcome the removal of a tyrant, and that the reconstruction of Iraq will involve many countries and a United Nations role.
Perhaps that will allow us to recover some of the legitimacy after the fact that the administration squandered before the war.