Threatening war seems to be working. Iraq is making concessions, and the inspectors are satisfied that their work is keeping things moving in the right direction. NATO wants to give them more time. Our friends are closer to the potential war zone, and they want to exercise more caution than we do.
War itself would undo any good the threat of it has done, and would create scars that wouldn't heal for a long time. It would get the U.S. and whatever allies it can muster into the business of setting up and propping up a puppet government in a country halfway around the world. In a time of economic distress, the aftermath of war could drain our resources even more than the war would.
Of course, the advantage would be that the oil barons backing the war would help the "people" of Iraq build up their "infrastructure," with an eye toward "economic revitalization" and "stability." Yeah, that's what'll happen, because we're always looking out for the well-being of those with fewer advantages.
Even if I thought war were a good idea, there's still no compelling reason to rush into it before other methods have a chance to work. There's no clear, imminent danger. No one else in the world sees things the way the Bush administration does. Even Germany is against a war. Doesn't that tell him something?