Even as the Senate voted, House leaders were hunting for the 12 votes they would need to turn around Monday's 228-205 defeat. They were especially targeting the 133 Republicans who voted "no," which includes Rep. Rob Bishop, R-Utah.

Their opposition appeared to be easing after the Senate added $110 billion in tax breaks for businesses and the middle class, plus a provision to raise, from $100,000 to $250,000, the cap on federal deposit insurance.

They were also cheering a decision Tuesday by the Securities and Exchange Commission to ease rules that force companies to devalue assets on their balance sheets to reflect the price they can get on the market.

There were worries, though, that the tax breaks would cause some conservative-leaning Democrats who voted for the rescue Monday to abandon it because it would swell the federal deficit.

"I'm concerned about that," said Rep. Steny Hoyer, D-Md., the majority leader.

As revised by the Senate, the package extends several tax breaks popular with businesses. It would keep the alternative minimum tax from hitting 20 million middle-income Americans and provide $8 billion in tax relief for those hit by natural disasters in the Midwest, Texas and Louisiana.

It doesn't designate a way to pay for many of the tax cuts, though, angering the House's band of conservative "Blue Dog" Democrats, of which Rep. Jim Matheson, D-Utah, is a member.

Leaders in both parties, as well as private economic chiefs everywhere, said Congress must quickly approve some version of the bailout measure to start loans flowing and stave off a potential national economic disaster.

"This is what we need to do right now to prevent the possibility of a crisis turning into a catastrophe," Obama said on the Senate floor. In Missouri, before flying to Washington to vote, McCain said, "If we fail to act, the gears of our economy will grind to a halt."

Critics on the right and left assailed the rescue plan, which has been panned by their constituents as a giveaway for Wall Street and has little obvious direct benefit for ordinary Americans.

Conservative Sen. Jim DeMint, R-S.C., said the step was "leading us into the pit of socialism."

Sen. Bernie Sanders of Vermont, an independent who's a self-described socialist, said the rescue was fundamentally unfair.

"The masters of the universe, those brilliant Wall Street insiders who have made more money than the average American can even dream of, have brought our financial system to the brink of collapse," Sanders said, and are demanding that the middle class "pick up the pieces that they broke."