Key lawmakers are ignoring a warning by the Federal Reserve chairman, Ben Bernanke, that “absent a plan,” the financial markets will worsen.

Most members of the Senate’s Banking Committee yesterday told Mr. Bernanke and Treasury Secretary Paulson, who had come to Congress seeking $700 billion in bailout money, either that they disapproved of a bailout in general, or that they were against the one the Bush administration was pitching.

Some senators balked at the idea of making taxpayers nationwide pay to clean up Wall Street’s mistakes.

“This massive bailout is not a solution,” Senator Bunning, a Republican of Kentucky, said. “It’s financial socialism and it’s un-American.”

Others appeared to agree with the idea of government bailout in principle, but criticized the administration for pushing a plan that said little about how the Treasury Department would go ahead with purchasing the illiquid mortgage-related assets that now clog Wall Street.

Senator Schumer urged a more cautious, piecemeal approach, asking Mr. Paulson whether, instead of seeking $700 billion for a bailout, the Treasury Department could settle for $150 billion now and see what effect that had on aiding the economy.

Mr. Paulson said yesterday that financial institutions including big banks, small banks, savings and loan associations, and credit unions would all be eligible to participate in the administration’s plan.

On Sunday, Mr. Paulson said “the intent right now” was not to include hedge funds in the bailout. Yesterday, a congressional staffer said that, under the proposal being negotiated currently on the Hill, hedge funds would not be excluded from participating.

Mr. Paulson’s responses to questioning by senators provided little detail about how a government bailout fund would function. He said there “would be different approaches in different situations” to how the Treasury Department would conduct reverse auctions for purchasing various types of mortgage-related assets from financial firms.

“We’re going to need to get really good asset managers,” Mr. Paulson said.

Repeatedly during the hearing, which lasted more than four hours, Mr. Paulson began his responses by saying: “I share your frustration.”

At one point, however, Mr. Paulson appeared frustrated at the lawmakers themselves for asking why, in essence, taxpayers should be hit up for cash to cover Wall Street’s mistakes.

“When you ask about taxpayers being put on the hook,” Mr. Paulson said, “guess what? They’re already on the hook.”

Mr. Bernanke, who sat beside Mr. Paulson, gave dark predictions about what would happen if the market were left to its own doings and how hard times would spread further across the country.

“We have a serious ‘too big to fail,’ problem in this economy,” the chairman of the Federal Reserve said.

“The financial markets are in quite fragile condition and I think absent a plan they will get worse,” Mr. Bernanke said. “I believe if the credit markets are not functioning, that jobs will be lost, that our credit rate will rise, more houses will be foreclosed upon, GDP will contract, that the economy will just not be able to recover in a normal, healthy way.”

Messrs. Bernanke and Paulson will testify before the House Financial Services Committee today. The House has, so far, appeared to be more amenable to the plan than the Senate.

Fearing that the bailout would stall before Congress, Vice President Cheney visited behind closed doors with a large group of Republican lawmakers yesterday to try to rally support. The bailout is likely to fail without Republican support, even if a substantial number of Democrats view it as necessary.

“The only thing really clear among Democrats is we don’t want to vote for this unless the Republicans do,” Rep. Brad Sherman, a Democrat of Southern California who is on the Financial Services Committee, said in a telephone interview. He continued later: “Even the people who want to vote for this bill say we shouldn’t vote for it unless they vote for it. People aren’t going to like this bill and we want them to think of it as a Republican bill.”

Up until yesterday, the question of executive compensation had been a sticking point between Democrats and the Bush administration proposal.

The Senate minority leader, Mitch McConnell, told reporters yesterday that he supported putting limits on how much companies that accept money from the bailout fund should be able to pay their executives. Democrats had previously called for that condition, which Republican had been expected oppose. Mr. Paulson had suggested that using the bailout to cap executive compensation would undermine the whole effort by discouraging companies from participating.

Senators McCain and Obama have each called for the bailout to include limits on CEO pay.

“This plan cannot be a welfare program for Wall Street executives,” Mr. Obama said yesterday from Clearwater, Fla. As other legislators have also demanded, Mr. Obama said there must be an oversight board to review the way any bailout money is spent.

Mr. McCain struck an aggressive tone in favor of quick passage of the bailout plan, echoing some of the points Mr. Bernanke made earlier in the day.

“Further inaction is simply not an option,” Mr. McCain said from Freeland, Mich. “We must pass legislation to address this crisis.

Mr. McCain, who also called for an oversight board, said that no senior executive whose company receives bailout money should “be making more than the highest-paid government official.

He called the plan “a great burden,” saying it would require about “a $10,000 contribution per household.”