The goal is to net at least 12 more House votes than the rescue proposal received Monday, when lawmakers rocked the political and financial worlds by rejecting it.
The gambit is certain to anger some conservative House Democrats, who object to tax cuts that are not offset with spending cuts. But Senate strategists assume it will gain more House votes than it will lose.
If so, Congress would be poised to pass landmark legislation giving the government billions of dollars to buy deeply discounted mortgage-backed securities that are choking off credit and roiling the markets.
The strategy is risky because some House members might see it as a high-handed move by senators. Senate passage of a bailout measure has seemed assured all along. The showdown is in the House, but now the Senate is trying to force the House's hand.
Sen. Charles Schumer, D-N.Y., called it "a brilliant move" that will "help pick up votes on both sides of the aisle."
House Speaker Nancy Pelosi's reaction was much cooler. "The Senate has made a decision about how to proceed and what can pass that body," the California Democrat said. "The Senate will vote tomorrow night, and the Congress will work its will."
The new approach, announced Tuesday night by Senate Majority Leader Harry Reid, D-Nev., and Minority Leader Mitch McConnell, R-Ky., would tack large and contentious tax measures to the bailout bill. Senate leaders figure the House will have to approve it because the tax cuts are too appealing to Republicans and the financial rescue plan will still seem essential to most Democrats.
The Senate approach uses big, game-changing amendments. House leaders earlier were considering the smallest possible tweaks to the bill in hopes of picking up 12 more votes. The previous compromise agreement met stiff opposition in the House, with many lawmakers facing fierce opposition to any bailout deal from their constituents.
Just a day after Republican Joe Barton helped kill the bailout bill in Congress, he returned home to his rural Texas district where he received support from his constituents, reports CBS News correspondent Bob Orr.
"I think we just ought to start over and come up with a plan that puts the taxpayer first," Barton told CBS News.
The Senate bill would raise federal deposit insurance limits to $250,000 from $100,000, as called for presidential nominees Barack Obama and John McCain only hours earlier.
House Minority Leader John Boehner, R-Ohio, praised the move, but many Democrats had signaled approval as well.
McCain, Obama and Sen. Joe Biden of Delaware, the Democratic vice presidential nominee, signaled plans to return to Washington for the Wednesday night vote. If Obama and Biden vote for the measure, it would make it more difficult for Pelosi and other Democrats to reject or change the Senate measure.
The Senate measure will graft the bailout language to a tax bill it approved last week, on a 93-2 vote. It includes: a provision to prevent more than 20 million middle-class taxpayers from feeling the bite of the alternative minimum tax, $8 billion in tax relief for those hit by natural disasters in the Midwest, Texas and Louisiana and some $78 billion in renewable energy incentives and extensions of expiring tax breaks.
In a compromise worked out with Republicans, the bill does not pay for the AMT and disaster provisions but does have revenue offsets for part of the energy and extension measures.
That wasn't enough earlier this year for the House, which insisted that there be complete offsets for the energy and extension part of the package.
The Senate version also may include a measure to require health plans for 51 or more employees to give equal treatment to mental health or addiction if they cover such illnesses. The House and Senate have passed similar mental health parity measures, but none has gone to Bush for his signature.
The surprise move capped a day in which supporters of the imperiled economic rescue fought to bring it back to life, courting reluctant lawmakers with a variety of other sweeteners including the plan to reassure Americans their bank deposits are safe.
Amid Tuesday's negotiations, Federal Deposit Insurance Corp. chairman Sheila Bair asked Congress for temporary authority to raise the limit on deposits by an unspecified amount. That could help ease a crisis of confidence in the banking system, Bair said.
She said the overwhelming majority of banks remain sound but an increase in the cap would help ease a crisis of confidence in the banking system as well as encourage banks to begin more lending.
Monday's House vote was a stinging setback to leaders of both parties and to Bush. The administration's proposal, still the heart of the legislation under consideration, would allow the government to buy bad mortgages and other deficient assets held by troubled financial institutions. If successful, advocates of the plan believe, that would help lift a major weight off the already sputtering national economy.
Bush renewed his efforts to save the bailout plan Tuesday, speaking with McCain and Obama and making another statement from the White House. "Congress must act," he declared.
Though stock prices rose, more attention was on credit markets. A key rate that banks charge each other shot higher, further evidence of a tightening of credit availability.
The rescue package was Topic A on the presidential campaign trail.
"The first thing I would do is say, 'Let's not call it a bailout. Let's call it a rescue,"' McCain told CNN. He said, "Americans are frightened right now" and political leaders must give them an immediate solution and a longer-term approach to the problem.
Obama issued a statement saying that significantly increasing federal deposit insurance would help small businesses and make the U.S. banking system more secure as well as restore public confidence.
Wall Street Rebounds On Bailout Hopes
Wall Street snapped back Tuesday after its biggest sell-off in years amid growing expectations that lawmakers will salvage a $700 billion rescue plan for the financial sector. But the seized-up credit markets where businesses turn to raise money showed no sign of relief.
The recovery in stocks wasn't unexpected as carnage on Wall Street often attracts bargain hunters, though questions remain about how investors will proceed. Without a bailout plan in place to absorb soured mortgage debt and other bad loans from battered banks, investors are left wondering what might restore confidence in lending.
Major stock indexes were almost a sideshow during the session, with the credit markets as the main event. A key rate that banks charge to lend to one another shot higher, a tightening of the availability of credit that could cascade through the economy.