WASHINGTON — In reluctantly tossing a $17.4 billion government lifeline to General Motors and Chrysler yesterday, President Bush assured that the automakers would not fail in coming weeks — sparing both the economy and his own legacy another potentially devastating blow. But Bush's action leaves most of the tough decisions about the U.S. auto industry's future to President-elect Barack Obama.

The conditions Bush attached to the emergency loans, such as requiring unions to accept wages and benefits comparable to those at U.S. factories run by foreign automakers, were largely nonbinding and thus subject to change by the next president.

That may mean a far different future for U.S. automakers from what many analysts have been predicting.

Obama consistently has echoed Bush's call for major restructuring by U.S. automakers to assure their long-term viability in a changing global marketplace.

But Obama might have a much different view of what constitutes viability. Obama has called not just for keeping Detroit alive but for making it a world leader in fuel-efficient, environmentally friendly vehicles.

"This is clearly a temporary measure," said Mark Oline, an analyst with the credit rating enterprise Fitch Ratings. "We expect the agreement will be significantly reworked once the new Congress and the new administration take office."

GM and Chrysler have said they needed a total of $14 billion by March 31 or they could face bankruptcy. Ford said it does not need short-term funding but warned that a failure by its competitors could endanger it as well.

The United Auto Workers union and some Democratic lawmakers were calling on Obama yesterday to change some of the conditions.

Obama called the bailout a "necessary step" and warned GM and Chrysler executives not to squander the chance to remake their firms because "the American people's patience is running out."

PREVENTING COLLAPSE

Bush's announcement yesterday ended a monthlong drama that saw the chief executives of Detroit's Big Three trek to Washington, D.C., twice to ask Congress for emergency loans for their companies and the millions of people whose jobs directly or indirectly rely on them — only to be rebuffed.

"There is too great a risk that bankruptcy now would lead to a disorderly collapse of the auto companies," Bush said. "My economic advisers believe that would deal an unacceptably painful blow to hardworking Americans far beyond the auto industry ... and send our suffering economy into a deeper and longer recession."

GM Chief Executive Richard Wagoner and other GM executives provided few new details of how they would restructure their company beyond the plan they submitted to Congress this month.

"We know we have a lot of work in front of us to accomplish this plan," Wagoner said at a news conference in Detroit yesterday. "We look forward to proving what American ingenuity can achieve."

GM stock shot up 23 percent yesterday to $4.49. Chrysler is privately held.

CONDITIONAL RESCUE

The plan announced by the White House is similar to one crafted with congressional Democratic leaders this month. The legislation was blocked largely by strong opposition from Senate Republicans, who said bankruptcy was the only way to force U.S. auto companies to make major changes.

The plan proposed in Congress would have taken the loan money from an existing $25 billion fund to help automakers retool their factories to produce more fuel-efficient vehicles.

With Bush unable to use that fund for a bailout without congressional approval, he agreed to Democratic demands to use money from the $700 billion financial rescue fund. Several Republicans sharply criticized Bush for that yesterday.

Under the White House plan, the Treasury Department will provide $13.4 billion in short-term loans to GM and Chrysler from the first half of the $700 billion fund. An additional $4 billion would be available Feb. 17 assuming Congress approves the second half of the $700 billion fund. GM will get about $9 billion of the initial allocation, while Chrysler will receive $4 billion.

GM and Chrysler must attain long-term financial viability by March 31, the White House said, or they will have to repay the loans immediately. They must deliver restructuring plans by Feb. 17 showing they can achieve a "positive net present value," or that their cash flowing in will outweigh cash flowing out.

Other conditions include a ban on stock dividends, limits on executive compensation, compliance with federal fuel efficiency standards and the provision of warrants to the government to purchase nonvoting stock equal to 20 percent of the loan amount.

The White House's restructuring targets include eliminating a jobs bank that pays laid-off workers; making wages and benefits competitive with U.S. workers for foreign automakers; and requiring the UAW to take at least half of future payments into a retiree benefit trust in the form of company stock.

Even with the emergency federal loans, the bankruptcy risk for all three companies remained "very high," said Gregg Lemos-Stein, a credit analyst with Standard & Poor's Corp.