President Bush and Senator Kerry are honing their debating skills, even as their campaigns and debate organizers keep haggling over details of the high-stakes, face-to-face matchups set to begin in Florida on Thursday.

Although the two campaigns announced a written agreement last week governing the most minute details of the debates, the organization that has sponsored all presidential debates since 1988, the Commission on Presidential Debates, has balked at some aspects of the deal.

In addition, the television networks that typically arrange camera feeds from the event said they had no desire to sign an agreement that precludes them from showing the reaction of one candidate while the other is speaking.

“Our initial reaction was we wouldn’t sign it,” one network official said.

Another person involved in the talks said all of the journalists who were named as moderators for the debates have declined to sign the ground rules drafted by the two campaigns.

The debate commission, a nonprofit organization with no official imprimatur, blew off a deadline the campaigns had sought to impose and later sent a letter saying it would make a “good faith effort” to abide by the agreement. While some details remain unsettled, the commission’s staff is already on site at the University of Miami, where the first debate is scheduled to take place.

Experts interviewed yesterday said the debate pact appeared to give a leg up to Mr. Bush.

“It’s always a dance between the two parties and the brain trust of the two candidates,” said a professor of communications at Boston University, Tobe Berkowitz. “Both are trying to accrue advantage. In this case, the Bush people certainly seem to have things going their way.”

The debate rules forbid the candidates to approach one another or use any signs or props. Signal lights indicating how long a candidate has remaining for his answer will be visible to the audience. If the moderator fails to enforce the time limits, then producers are to sound a bell or buzzer to remind viewers that the candidate has exceeded his time. The two campaigns also agreed not to allow the candidates to question each other directly.

The director of a study that proposed model standards for political debates said that having the campaigns negotiate the terms of debate can make the events less lively and less informative.

“All of that works against the public interest in terms of getting the public the most interesting and useful information from the debates,” said Ronald Faucheux, who studied debate formats for the Pew Charitable Trusts.

Mr. Faucheux said surveys have shown that voters would rather see the candidates question each other than see them take questions from a journalist.

“It’s an opportunity to zero in on areas of disagreement,” he said. “Voters like candidate-to-candidate questioning because they feel like it gets candidates to engage.”

Both campaigns said yesterday they expect the disagreements with the press and the commission to be resolved shortly. Each of the campaigns also continued yesterday to try to diminish expectations for its candidate.

One of Mr. Bush’s top strategists has repeatedly referred to Mr. Kerry as “the greatest debater since Cicero.”

The Democratic Party chairman painted Mr. Bush as a modern-day master of political debate. “George Bush is a great debater,” Terence McAuliffe told reporters. “George Bush has never lost a debate. He wins them on style, not substance.”

Mr. Berkovitz, the Boston professor, said it will be tough for Democrats, who have disparaged the president’s intellectual and rhetorical skills for years, to make the case now that Mr. Bush is actually a skilled debater.

“You can’t have spent all this time and media power denigrating Bush and suddenly say he’s much sharper than you give him credit for. The drumbeat for four years has been, this guy isn’t the sharpest knife in the drawer. So you can’t have it both ways,” Mr. Berkovitz said.

While Mr. Bush remained out of the public eye yesterday at his Texas ranch, he was not silent. Fox News released excerpts of an interview that one of the network’s hosts, Bill O’Reilly, conducted recently with the president.

Mr. Bush said that America is intent on preventing Iran from developing a nuclear weapon, and that he would consider a military response if talks aimed at persuading the Iranians to dismantle their nuclear program are unsuccessful.

“All options are on the table, of course, in any situation, but diplomacy is the first option,” Mr. Bush said. “We’ve made it clear. Our position is they won’t have a nuclear weapon.”

Mr. O’Reilly also asked Mr. Bush whether, if he could make the decision again, he would have flown to the aircraft carrier where he spoke in May 2003 beneath a banner declaring “Mission Accomplished” in Iraq.

“Absolutely,” Mr. Bush said. “You bet I’d do it again.” The president did not address whether he should have used different language in describing the conditions in Iraq.

The comment drew a prompt and tart reply from Mr. Kerry as he arrived in Wisconsin to campaign and continue with his preparation for the upcoming debates.

“Just this morning, we learned he would do it all over again and dress up in a flight suit and land on an aircraft carrier and say, ‘Mission accomplished,’ all over again,” Mr. Kerry said. “I will never be a president who just says, ‘Mission accomplished.’ I will get the mission accomplished.”

Mr. Bush’s upbeat public assessments of the situation in Iraq were undercut somewhat yesterday by Secretary of State Powell, who acknowledged twice during an ABC interview that terrorists have caused increasing violence there in recent weeks.

“It’s getting worse, and the reason it’s getting worse is that they are determined to disrupt the election. They do not want the Iraqi people to vote for their own leaders in a free democratic election,” Mr. Powell said on the “This Week” program. “Because it’s getting worse, we will have to increase our efforts to defeat it, not walk away and pray and hope for something else to happen.”

The campaigns have agreed that Thursday’s debate will be devoted to foreign policy. As a result, Iraq is expected to be the major subject of discussion.

One presidential candidate not pleased with the plan for debates is Ralph Nader, who has not been invited to any of the three planned exchanges. The commission said it is excluding Mr. Nader because he did not reach a 15% threshold in public opinion polls. In addition, it’s not clear whether the independent candidate and consumer activist will be on enough state ballots to win the election, even if he could muster the votes.

A spokesman for Mr. Nader said the commission’s system is effectively rigged to prevent third-party candidates from debating.

“It’s really a partisan process put in place by the two parties to keep third parties out,” said the spokesman, Kevin Zeese.

In 2000, the debate commission gave security guards “facebooks” with pictures of third-party candidates such as Mr. Nader and instructed the guards to prevent those in the photos from entering, even with valid tickets.

Last month, a federal judge said the FEC was wrong to dismiss a complaint that the debate commission was acting as a prop of the two major parties.

“The exclusion policy appears partisan on its face,” wrote the judge, Henry Kennedy Jr.

Efforts to reach the commission for comment yesterday were unsuccessful.