Clinton, Obama take center stage at Iowa debate - The two dominate as participants and as topics of discussion.

Whether it was the early hour -- the local starting time was 8 a.m. -- or the churchly sanctity of a Sunday morning, the session was among the tamest of the campaign season. Much of the 90-minute program was dominated by the two front-runners, Sens. Hillary Rodham Clinton of New York and Barack Obama of Illinois, both as participants and as topics of discussion.

The first question from moderator George Stephanopoulos of ABC News went to the heart of what many Democrats are mulling over: whether Obama is too inexperienced and Clinton too divisive to be elected president.

The candidates were read some of the harsher remarks they have uttered on the campaign trail. For the most part they declined to repeat them on stage at Drake University, with one exception: Sen. Joseph R. Biden Jr. of Delaware did not back away from his assertion that Obama, who is midway through his first Senate term, lacked the seasoning to be president. "I stand by the statement," Biden said.

Sen. Christopher J. Dodd of Connecticut also took a veiled shot at Obama. "You're not going to have time in January of '09 to get ready for this job," said Dodd, a veteran of more than three decades in Congress.

But Clinton, who has accused Obama of naivete in foreign affairs, offered no such criticism Sunday. "I'm running on my own qualifications and experience," she said, adding that "it's really up to the voters" to parse the differences among candidates.

Obama, who quipped that he prepared for the debate by riding the bumper cars at the nearby Iowa State Fair, similarly declined to engage on the question of whether Clinton was too polarizing to win the White House, a criticism implicit as he campaigns across the country.

With Clinton standing on the opposite end of the stage -- their positioning determined by lot -- Obama said he believed that any candidate who won the Democratic nomination would prevail in November 2008. The primary selection process starts here in Iowa, with precinct caucuses scheduled for January.

Obama took a more indirect swipe at his chief rival. "What I'm suggesting is that we're going to need somebody who can break out of the political pattern that we've been in over the last 20 years," he said. Asked whether Clinton was part of the troublesome status quo, Obama said he would not be running if he did not believe he was the candidate best able to break with the past.