Ms. Pelosi sharply criticized the Bush administration on Wednesday over the $85 billion bailout of A.I.G., saying it was evidence of mismanagement by President Bush. But she expressed strong support for the automakers’ loan guarantees, which would be used to help the companies meet new fuel efficiency standards that Congress adopted last year.

“We see that as a way to rebuild and strengthen the technological base of America,” Ms. Pelosi said at a news conference in the Capitol. “It would certainly help people in the auto industry, but it’s not only about the auto industry, it’s about the auto industry, it’s about our economy, it’s about America’s work force.”

She added: “We consider this a major investment in innovation.”

Republican Congressional leaders, too, said they were in favor of helping the automakers. Representative Adam Putnam of Florida, the third-ranking House Republican, said at a news conference that it was up to auto executives to convince lawmakers of the need for government assistance.

“It’s incumbent on them to make the case to Congress that it is a loan guarantee, that it is a wise investment of taxpayer dollars, and I think that they are on the Hill this week making that case,” Mr. Putnam said. “The reports that I have heard from my colleagues is that they have been fairly persuasive.”

Image Robert L. Nardelli of Chrysler said he was encouraged. Credit... Chip East/Reuters

The Senate majority leader, Harry Reid of Nevada, expressed his own support for aid to the automakers at a news conference on Wednesday morning. Mr. Reid said the loan guarantees, which would cost taxpayers $7.5 billion, were needed.

“I think it’s extremely important that we try to do something,” he said. “These are jobs. These are cars that we should be selling  or manufacturing in America, not someplace else.”