April 27 (Bloomberg) -- Senator Barack Obama and former Senator John Edwards sought during the Democrats' presidential debate to put front-runner Hillary Clinton on the defensive over her 2002 vote authorizing President George W. Bush to use force against Iraq.

Clinton, 59, a New York senator, held her own last night, repeating her explanation that, had she known then what she knows now about Iraq, she wouldn't have made the same decision.

``If this president does not get us out of Iraq, when I'm president, I will,'' Clinton said.

National security issues, from the war in Iraq to U.S. policy toward Russia, dominated the forum in South Carolina.

Obama, 45, who wasn't in the Senate in 2002, sought to contrast his initial opposition to the war with Clinton's stance: ``I am proud that I opposed this war from the start, because I thought that it would lead to the disastrous conditions that we've seen on the ground in Iraq,'' said Obama of Illinois.

Edwards, who also initially backed the war, set himself apart from Clinton by confessing that his vote was a mistake.

``I was wrong to vote for this war,'' said Edwards, 53, of North Carolina. ``Senator Clinton and anyone else who voted for this war has to search themselves and decide whether they believe they've voted the right way.''

Poll Standings

A Wall Street Journal/NBC News poll taken April 20-23 found 36 percent of people surveyed supported Clinton, while 31 percent backed Obama. Edwards garnered support from 20 percent of the 1,004 adults surveyed. Some state polls taken in New Hampshire, Iowa, Nevada and South Carolina, the first states to pick delegates for the party's nominating convention, show an even tighter race.

``In terms of the polls, I don't think we are going to see much changed based on tonight's debate performances,'' said Mitchell McKinney, a communications professor at the University of Missouri.

The most provocative statements of the night came from the lesser known candidates, Ohio Representative Dennis Kucinich and former Alaska senator Mike Gravel. Kucinich said Clinton, Edwards and two other candidates at last night's debate, Delaware Senator Joseph Biden, 64, and Connecticut Senator Christopher Dodd, 62, should have known better than to back the use of force against Iraq.

`Frighten Me'

``I don't think that it's sufficient to say that if we had the information at the beginning that we would have voted differently. That information was available to everyone,'' said Kucinich, 60. Gravel, 76, who also opposed the war, said the other candidates ``frighten me.''

The discussion covered a wide range of topics, including Iran, Russia, abortion and health care.

``It would be a profound mistake for us to initiate a war with Iran,'' Obama said. ``But, have no doubt, Iran possessing nuclear weapons will be a major threat to us and to the region.'

On Russia, Edwards said what the U.S. ``should be asking ourselves is how does America change the underlying dynamic of what's happening in the world?''

For that to happen, ``The world has to see America as a force for good again.''

Wal-Mart

Clinton was asked whether Wal-Mart Stores Inc., the world's largest retailer, was good or bad for the U.S. The company has been a target of criticism by unions and others that it doesn't provide employees with fair wages or benefits.

``It's a mixed blessing,'' said Clinton, who served on the Bentonville, Arkansas-based retailer's board from 1986 to 1992. ``When Wal-Mart started, it brought goods into rural areas'' and ``gave people a chance to stretch their dollar further.''

As the company grew bigger, though, it ``raised serious questions'' about health care, workplace safety, and job discrimination, she said.

The candidates got in some digs at each other.

New Mexico Governor Bill Richardson, 59, perhaps thinking of Edwards, who reimbursed his campaign for a couple of $400 haircuts, said, ``I think the American people want candor. They don't want blow-dried candidates with perfection.''

`High-Falutin'

Edwards, referring to Obama, who has faced criticism for not producing a clear plan for dealing with health-care costs, said, ``Rhetoric's not enough. High-falutin' language is not enough.

``I'm proud of the fact that I have a very specific universal health-care plan, which I think is different than some others on the stage who are running for president,'' Edwards said.

Obama responded by outlining a series of steps he supports, including establishing a national insurance pool that the uninsured can buy into and subsidies for those who can't afford group rates.

One of the few surprises of the night was when Biden, known for his verbosity, was asked by moderator Brian Williams if he could avoid long-winded gaffes as president.

Biden's one-word answer: ``Yes.''

To contact the reporter on this story: Kim Chipman in Washington at kchipman@bloomberg.net.

Last Updated: April 27, 2007 06:49 EDT