Debate uncertainty keeps the political stakes high

After showing up for a White House meeting on the administration's troubled bailout proposal -- and sitting at opposite ends of a large oval table -- the candidates appeared no closer to breaking their impasse.

On Thursday night, Obama urged McCain to join him at the University of Mississippi.

"Sen. McCain has no reason to be fearful about a debate," the Democrat told reporters in Washington. "He's got his personal, strong opinions, and you know he's been expressing them on the campaign trail. This does give us an opportunity to go back and forth."

Aides to McCain, the Republican senator from Arizona, reiterated his intention to stay in Washington until a legislative agreement is reached, even if it means skipping tonight's session, the first of three debates planned between now and mid-October.

"With so much on the line, for America and the world, the debate that matters most right now is taking place in the United States Capitol, and I intend to join it," McCain told a New York audience before flying to Washington to join the bailout talks.

University officials, the major television networks and the nonpartisan commission sponsoring tonight's debate all indicated they would proceed on the assumption McCain would show up in the end. But the prospect he might skip the debate -- which would be unprecedented -- only elevated the political stakes.

"I could see it cutting either way," said John J. Pitney, Jr., a government professor at Claremont McKenna College. "Obama could cast this as McCain's effort to duck debates, and McCain could cast it as Obama putting political interests ahead of national interests. Since this is totally uncharted waters, I don't know whose interpretation is going to win."

With the race so close, the presidential debates could prove pivotal.

"It's a critically important moment in the campaign for both candidates," said Paul Maslin, a Democratic strategist who is not affiliated with the Obama campaign. "There's a large number of people who probably stayed away from the two conventions and ignored most of the ads and the noise on cable television who will tune in to watch these debates."