CLEARWATER, Fla. — Barack Obama and John McCain offered more details yesterday about what they would do to bail out the nation's struggling financial institutions, with both demanding remedies that provide greater oversight and taxpayer protections.

The presidential rivals held dueling news conferences devoted to the financial crisis, on a day when congressional leaders balked at the Bush administration's $700 billion plan to buy troubled investments that have shaken some of the most venerable financial firms on Wall Street.

Both candidates are struggling with the fallout from a financial crisis that neither had foreseen. Obama conceded that as president he might be compelled to defer pieces of his $130 billion-a-year spending plan if the economy worsens. McCain has been forced to re-examine his long-held view that free market solutions work best, and now finds himself calling for tougher regulation.

For all their disputes, the plans put forward by the pair are nearly identical in important respects.

Both candidates said they are uncomfortable with the sweeping powers the Bush proposal would give to the secretary of the Treasury. They recommended creation of an independent board that would oversee the rescue.

Each is calling for measures that would permit taxpayers to recoup some of the public money sunk into the deal. Obama wants to impose a "financial stability fee" — charged to financial institutions — that would be used to repay households for the massive public outlay.

Striking a populist chord, McCain and Obama both say that Wall Street executives should not be able to collect excessive payouts as a result of a government bailout.

Yet differences remain. Obama said he would like to see an economic stimulus package for families struggling to pay bills and stave off foreclosure.

McCain, meeting reporters at a Dow Corning Corp. solar panel factory in Freeland, Mich., made it clear that he would not support such a stimulus package. McCain said he will seek "basic improvements" to the legislation as it moves forward.

To protect taxpayers, he asked for a bipartisan board to provide oversight, a plan to recover the money, a cap on compensation for executives of firms that are helped by the bailout and a ban on earmarks on the legislation. McCain stopped short of saying he would vote "no" if his priorities weren't reflected. He said he was confident the final plan would include them.

An open question is how far McCain and Obama will push to see their principles folded into the rescue plan. At a news conference here, Obama was asked if he would vote against the bill if his proposals are disregarded.

He gave an answer that left him maneuvering room: He said if that happens he will urge Paulson to "go back to the drawing board" and return with a different proposal. "The principles I outlined are principles I believe any package needs to contain for me to support it," he said.

With the markets reeling, Obama conceded he may need to postpone parts of his ambitious policy plans.

Over the course of the campaign, Obama has promised to spend, among other things, $6 billion a year to improve the nation's bridges, roads and dams; $500 million a year to help religious and community groups provide summer education; $2 billion to aid displaced Iraqis; and $15 billion a year to develop cleaner energy sources.

In an interview shown yesterday on NBC's "Today Show," Obama asked, rhetorically, if he "can do everything that I've called for in this campaign." Answering his own question, he said he "probably" won't be able to fulfill all his promises "right away."

He returned to the subject later in the day. Some plans won't be deferred, including new education spending, energy research, a healthcare overhaul and his tax cut, Obama vowed. But he said he would re-evaluate his agenda once he takes office.

"It would be irresponsible of me to say I'm not going to take into account what things look like should I take office," he said. "And one of the big question marks ... is whether we have an economic recovery or we slide deeper into a recession. That will have a big impact on what federal revenues are and what the budget looks like."