A poll released by the Pew Research Center last week found that public support for keeping U.S. troops in Iraq had reached its lowest point since the 2003 invasion. Half the people questioned said they wanted to bring U.S. troops home as soon as possible, compared with 44 percent who said the troops should stay "until the situation is stabilized."

Reflecting the increasing partisan cast of the issue, Sen. Dianne Feinstein, D-Calif., in the Democratic response to Bush's radio address, called on the president to turn more responsibility for security over to the Iraqi government "so our troops can responsibly be redeployed." She added, "The administration's dangerous incompetence has made the job harder."

A former senior official said he did not expect political pressure to affect Bush's decisions on Iraq this year but warned that the 2008 presidential election could be a different story.

"There is deep concern in the White House that 2008 will be a referendum on Iraq," he said. "I don't think the president will be affected by the congressional elections. But in 2007, at some point, does he say: 'I'm going to do what's right, no matter what the political consequences'? Or does he say, 'We gave the Iraqis every chance; we can't want a successful Iraq more than the Iraqis want it'?

"Leaving Iraq in its current state would be a very serious strategic setback for us," he said. "It would be a defeat. We can dress it up. We can try to recover from it. But it's a defeat."