The televised debates could have an unusually large impact on the presidential race this year, but organizers and candidates face an immediate challenge of making sure the first session this Friday, which is supposed to cover only foreign policy, does not seem strangely detached from the economic crisis facing America.

A statement issued Sunday by the Commission on Presidential Debates said the agreement among the panel, the Democratic nominee, Senator Obama of Illinois, and the Republican nominee, Senator McCain of Arizona, called for devoting Friday’s 90-minute debate at the University of Mississippi “exclusively to foreign policy.”

Given Mr. McCain’s national security experience, it might be expected that his camp would want to maximize the time spent on those questions. However, the Republican nominee’s campaign manager, Richard Davis, is insisting that he is eager to address the financial turmoil.

“We hope that the moderators and others will give us an opportunity to address the economy as we go forward,” Mr. Davis said Monday in a conference call with reporters. “The debates obviously will have an inordinate impact on the election. … We’re locked in a very close battle.”

At the request of Mr. Obama’s campaign, the economy was made the focus of the third and final debate, set for October 15 at Hofstra University on Long Island. The second debate, scheduled for Nashville, Tenn., on October 7, has no particular issue focus and is to feature questions solicited from the audience and the Internet.

The chairman of the Democratic Party, Howard Dean, said yesterday that he sees no way to avoid the economy intruding on Friday’s session. “It’s inevitable that the economy is going to bleed into this,” Dr. Dean told MSNBC.

A spokesman for the debate commission, which is a self-appointed creation of former Democratic and Republican officials, said any turn to the economy on Friday would be up to the PBS journalist overseeing the session, Jim Lehrer. “It is and has always been up to the moderator to interpret the scope of the debate within the confines of the first debate being foreign policy and national security,” the spokesman, who asked not to be named, said. “The commission has zero role in that.”

“I don’t know of any debates since the 1980s and possibly the 1960s that seem to loom as large as these do,” a Democrat who advised Vice President Gore’s campaign in 2000 and Senator Kerry’s bid in 2004, Christopher Lehane, said. “The race has come down to a character test. … The public will not watch these debates like someone watches a debate between Harvard and Yale. They’ll watch it like they watch ‘The Simpsons.’ Who do you like?”

Democratic and Republican analysts said that, barring a major gaffe, the debates will turn on whether voters feel comfortable with Mr. Obama as president.

“The burden is really on Obama,” a Republican who managed Senator Dole’s 1996 campaign, Scott Reed, said. “Voters who say they’re undecided are becoming an endangered species. It’s up to Obama to try to close the deal. He’s having a difficult time getting them to support him because of trust issues.”

In the first debate, candidates may give a two-minute answer to each question. Each pair of answers will be followed by a five-minute discussion in which the candidates are free to question each other about their responses.

Mr. McCain is expected to work in his debate preparations between other events this week, including meetings with foreign leaders in New York today. Mr. Obama veered off the campaign trail yesterday to prepare for the debates in Clearwater, Fla.

“Our opponent is preparing with a three-day debate camp. We expect a disadvantage that way,” a spokesman for Mr. McCain, Tucker Bounds, said. He also noted that Mr. Obama took part in more than 20 debates during the protracted Democratic primary.

A spokesman for Mr. Obama, Nicholas Shapiro, disputed the idea that Mr. Obama has the upper hand at this week’s face-off.

“John McCain has boasted throughout the campaign about his decades of Washington foreign policy experience and what an advantage that will be for him,” Mr. Shapiro said. “This debate offers him major home court advantage, and anything short of a game-changing event will be a key missed opportunity for him.”

Both campaigns were tight-lipped about the details of their preparations, though Mr. Obama’s camp has not disputed reports that a lawyer who worked for President Clinton, Gregory Craig, is playing Mr. McCain in mock debates.