The sobering news that the number of Americans killed in Iraq has risen to 4,000 prompts a review of how the United States got there and what it has achieved.

One of the troubling aspects of President Bush's decision, backed by the Congress, to go to war in 2003 was that the rationale for it was never very clear. Different reasons continued to be cited for the attack on Iraq.

One of them was that it possessed weapons of mass destruction that were a threat to the United States. Thorough investigation of that claim, once American forces had taken over in Iraq, showed that it wasn't true.

A second was that there were ties between Iraq and al-Qaida that also constituted a threat. As it turned out, that wasn't true either. Al-Qaida members are in Iraq now, but as a by-product of the long struggle of Iraqis and their allies against the United States as an occupying power.

Another suspected reason, given the oil-industry links of the Bush administration, was that America was going to seize Iraq to assure a key part of its external oil supply. Yet the effects of the war and Washington's failure to take solid steps in the Middle East peace process are part of the cause of the catastrophic energy situation Americans face at the gasoline pump.

A fourth reason was that an Iraq liberated by the United States and then schooled in democracy was going to serve as a beacon to other Middle Eastern countries. The current political and military situation in Iraq and neighboring countries shows just how false that presumption was.

Finally, there was the American political hypothesis that Mr. Bush needed to be a wartime president to win in 2004 the re-election his father didn't get in 1992. Iraq was the war. He was re-elected and the results, including the impact of his policies on the economy, are unfortunately clear.

So now Americans are faced with 4,000 dead, nearly 30,000 wounded, and financial costs, estimates of which run into the trillions of dollars. Saddest of all is the fact that the suffering of the families and friends of those killed and wounded in this conflict will be with us for a long time.

Mr. Bush can't face cutting the numbers of U.S. troops in Iraq during his term, fearful that the place will come unstuck if he does. His policy, and the Congress' continuing willingness to fund it, are disgusting and will be a permanent stain on American history.