OXFORD, Miss. — A day before the first nationally televised presidential debate between Sen. John McCain and Sen. Barack Obama, questions remained about whether the event would occur.

McCain, the Republican nominee, announced Wednesday he was suspending his campaign to devote attention to the nation's economic crisis and would not attend the debate.

He asked Obama, his Democratic counterpart, to do the same. But Obama said he saw no reason to cancel the debate, and the Commission on Presidential Debates said it would proceed with the forum scheduled for today at 3 p.m. Hawai'i time at the University of Mississippi.

While the debate topic was supposed to be foreign affairs, it would be virtually impossible to ignore the threat of financial calamity that has visited Wall Street investment banks, the broader economy and American taxpayers over the past 10 days.

"I can't think of a better opportunity to talk about a global financial crisis," Robert Gibbs, Obama's economic adviser, told reporters yesterday.

Gibbs said the Obama team "was prepared to take questions from Jim Lehrer whether John McCain is there or not."

The candidates met yesterday afternoon with President Bush and congressional leaders to discuss the crisis and the administration's $700 billion bailout proposal.

The threat of a meltdown of the nation's financial system and the Bush administration's plan for avoiding it has raised the debate stakes for both McCain, a 22-year senator from Arizona, and Obama, who is in his fourth year as senator from Illinois.

"Every race, the debate stakes are high, but they are higher this time — maybe because more people are informed about things this time, maybe because of the Internet, maybe because of no incumbent and maybe because the world seems to be going to hell in a hand basket," said Allan Louden, an expert in presidential debates at Wake Forest University.

McCain must address questions about his age — he recently turned 72 — knowledge of economic issues and party ties to an unpopular president, George W. Bush. Look for McCain to attack Obama as unprepared for the burdens facing the next president, while arguing he has differed from Bush on everything from the conduct of the war in Iraq to federal spending.

Louden said McCain "has to look like he is in charge without having ownership (of the problems), or he gets blamed for them."

McCain's advisers know what he is up against.

"This has certainly been an exclamation point in terms of what we face in terms of the economy," said Mike DuHaime, McCain's political director. "I think what voters are going to look at is who is best prepared to lead and who has that experience. ... I think that John McCain is that person."

Still, the latest economic news adds to an already sour environment for Republicans, who have held the White House for nearly eight years.

Conversely, Louden said, Obama can't afford to get "caught flat-footed" on an answer, for fear of looking unprepared.

Expect Obama to argue that the challenges facing the country — in both foreign and domestic affairs — demand change, and that only he can provide it. But at 47, and just four years removed from the Illinois Legislature, questions about Obama's experience are a hurdle.

Louden said the four debates spread over the next 19 days "could be the whole game" in 2008. And there are indications the first one could draw a huge audience, despite falling on an evening where many Americans are likely to be at high school football games. A bipartisan poll in 14 pivotal states taken Sept. 18 and 20 indicated 62 percent of respondents said they were very likely to watch the debate, which runs for 90 minutes.

A Quinnipiac University poll of Colorado, Michigan, Minnesota and Wisconsin indicated about a fourth of respondents said the upcoming debates could change their minds.

The other presidential debates will be held Oct. 7 at Belmont University in Nashville, Tenn., and Oct. 15 at Hofstra University in Hempstead, N.Y.

Vice presidential candidates Sen. Joe Biden, the Democrat from Delaware, and Alaska Gov. Sarah Palin, the Republican, will debate at Washington University in St. Louis next Thursday.

The first presidential debate traditionally has been the most important because it sets the tone. For many Americans, it is also the first chance to compare candidates on the same stage.

At Washington University in 1992, Bill Clinton made a change argument against a sitting president, the senior George Bush, while trumping third-party hopeful Ross Perot. Clinton won the White House less than four weeks later.

In 2000, Al Gore's audible sighing and eye-rolling condescension toward the younger Bush gave Bush a platform to appear cool-headed and amused.

Louden said he thinks Obama may have made a strategic error in not accepting other debates offered by McCain over the summer. In the end, Obama agreed to only those put on by the bipartisan Commission on Presidential Debates.