In their first debate in seven weeks, Obama said he mangled his description of the mood in economically struggling small towns and Clinton apologized for the first time for inaccurately saying she came under sniper fire in Bosnia in 1996.

The debate, which featured few heated confrontations but plenty of probing and positioning, seemed unlikely to dramatically alter the race six days before the next Democratic showdown in Pennsylvania.

Obama has been under heavy criticism from Clinton and Republican John McCain, who have called him elitist and out of touch for saying small-town residents were clinging to religion and guns in bitterness over their economic troubles.

"The problem that we have in our politics, which is fairly typical, is that you take one person's statement, if it's not properly phrased, and you just beat it to death, and that's what Senator Clinton's been doing," Obama said in the debate in downtown Philadelphia.

Clinton, who has eased off her public criticism of Obama over the remarks in the past two days but launched a television ad in Pennsylvania assailing them, said they were "a fundamental misunderstanding of religion and faith."

She warned the remarks would hurt Democrats if Obama won the nomination to face Arizona Republican Sen. John McCain in November's presidential election.

"Obviously, what we have to do as Democrats, is make sure we get enough votes to win in November," she said. "The Republicans, who are pretty shrewd about what it takes to win, certainly did jump on the comments."

Obama, an Illinois senator, responded, "Look, there is no doubt that the Republicans will attack either of us."

Clinton, a New York senator, apologized for her own recent campaign controversy, when she inaccurately said she had come under sniper fire when visiting Bosnia in 1996.

"You can go back for the past 15 months. We both have said things that, you know, turned out not to be accurate," Clinton said. "That happens when you're talking as much as we have talked. But, you know, I'm very sorry that I said it."

Obama seemed to speak for both of them when he chimed in, "For us to be obsessed with these kind of errors, I think, is a mistake."

Obama also had to defend himself in a recent controversy over inflammatory comments by his pastor, the Rev. Jeremiah Wright.

"I specifically said that these comments were objectionable. They're not comments that I believe in. And I disassociated myself with them," he said.

PENNSYLVANIA SHOWDOWN

The controversies have roiled the Democratic presidential race during a seven-week lull between the last round of major contests in Ohio and Texas on March 4 and next week's showdown in Pennsylvania.

Clinton has a dwindling lead over Obama in state polls, and needs a big win to try to close the gap on the Illinois senator in popular votes and pledged delegates to the nominating convention.

With 10 contests remaining, Obama has a nearly unassailable lead in pledged delegates, but neither candidate is likely to gain enough delegates to win without help from nearly 800 Democratic Party officials and insiders who are free to back any candidate.

When pressed whether she thought Obama could win in November and beat back attacks from Republicans, Clinton said: "Yes, yes, yes. Now I think that I can do a better job. Obviously that's why I'm here."

"I believe I am the better and stronger candidate than Senator McCain and I can go toe to toe with him on national security," she said.

Both candidates said they would move forcefully to ensure Iran does not acquire nuclear weapons, and would make it clear that an attack on Israel would prompt U.S. retaliation.

"I will do whatever is required to prevent the Iranians from obtaining nuclear weapons," Obama said.

The two candidates also agreed they would not raise taxes on Americans making less than $200,000 a year.

Obama was asked by a voter via video why he did not wear the American flag in his lapel.

"I have never said that I don't wear flag pins or refuse to wear flag pins. This is the kind of manufactured issue that our politics has become obsessed with and, once again, distracts us," he said.