Not since Vietnam has a presidential campaign been so caught up in foreign policy, but the crisp choice from that time — for or against a war — is missing now. President Bush and Democrat John Kerry (search) are not that far apart on Iraq.

Iraq, issue-watchers say, has staged its own invasion of sorts, a reciprocal shock and awe on the American political landscape. The candidates talk about many other things, but affordable-college plans and job programs just aren't holding a candle to the tumult abroad.

"The only issue driving the vote is Iraq," says Democratic pollster Celinda Lake. Even terrorism, by definition and experience a threat to Americans at home, trails faraway Iraq as a concern for voters.

That's not to say people can pick between a distinct Plan A and Plan B on the matter.

Apart from transferring limited authority to the new interim Iraqi government this week, Bush has taken steps to share the burden of Iraq's security with more countries, as Kerry has urged. And Kerry, for all his sharp criticisms of Bush's handling of the war, has proposed no radical shift.

"In many ways the difference comes down more to attitude than policy prescription," said Jon Alterman, director of the Middle East program at the Center for Strategic and International Studies (search).

"You don't see Kerry saying, 'I have a secret plan to win the war on Iraq.' You don't see Kerry saying, 'We should turn tail and come home.' You're seeing both of them talking about the need to manage this professionally."

In Bush, analysts discern a vision broader than Kerry has embraced of transforming Iraq into a full-fledged democracy. In Kerry, they see someone willing to work harder than Bush to make Iraq a true international responsibility and repair strained relations with other leaders.

But Charles Pena, director of defense policy studies at the Cato Institute, a private research group, questions whether that's much for voters to chew on. And he saw little chance the preoccupation with Iraq will dissipate now that sovereignty has been transferred — as long as U.S. forces remain tied down there and under assault.

"This sort of transcends who the president is," he said. "America was behind the president. Now America is saying this war wasn't worth it. The bottom line is, people want to know, when are the troops coming home? When do we stop paying for this?

"Anything short of that is not likely to have a significant impact on how people view the war."

Public opinion appears to be turning more negative on the Iraq war. For the first time, a majority in a recent Gallup poll said the United States made a mistake in sending troops to Iraq. A majority also said the war has made America less safe.

A similar turning point came in the summer of 1968, when a majority for the first time judged the Vietnam War a mistake. Still, Richard Nixon (search) defeated the anti-war Hubert Humphrey (search) that November.

Despite the erosion of support over Iraq policy, Bush's reputation as a leader — resolute in the minds of supporters, stubborn to opponents — has kept the race even with Kerry, who suffers in some polls from the suspicion that he waffles.

Some voters who don't like Bush are not convinced Kerry would do any better on Iraq or the war on terrorism. "Whoever comes after Bush has a mess to clean up," said Laura Clark, 39, of Randallstown, Md. But in the event of a terrorist attack, she would feel no safer with the Democrat, because "the advisers make the difference" in telling the president what to do.

Bush supporter Mark Jacobs, 54, of Houston, makes another cautionary point — that a politician who seeks advantage from the turmoil in Iraq does so at his peril.

"You finish the job and you don't do it for political gain," he said. "Don't use body counts as a political hammer."

All those crosscurrents complicate what would seem to be a straightforward calculation — that the persistent chaos in Iraq is a drag on Bush's prospects.

The rising casualties and sense of things spinning out of control have certainly not helped him, said Carroll Doherty, an editor at the Pew Research Center. Yet it's uncertain who gains if Iraq settles down and the nation's attention turns to domestic issues, believed to be Kerry's strong point.

"The irony is that stability in Iraq is obviously good news for Bush," he said, "but it also allows Kerry to get media attention on issues other than foreign policy."