General Motors Co.'s quick emergence from bankruptcy protection Friday gives President Barack Obama a much-needed dose of positive news amid questions on the effectiveness of his stimulus package.

But political analysts warn that the president's risky move to take over the world's second-largest auto maker could come to haunt his administration if the experiment fails.

"Like the stimulus bill, this then becomes a litmus test for what the administration wants to do," said Julian Zelizer, a professor of history and public affairs at Princeton University. "If it doesn't work out, if it becomes a failure itself, then it's not just about GM or the economy. It's part of the administration."

Poll numbers show that Americans are increasingly wary of the government's auto-industry bailout, underscoring the political risks posed to Obama. Nearly seven in 10 respondents in a Wall Street Journal/NBC News survey last month said they had concerns about federal interventions into the economy, including Obama's decision to take an ownership stake in GM.

The U.S. takeover of GM - the government will hold a roughly 60% stake in the company after investing $50 billion in its restructuring - is part of a series of bold moves that will come to define Obama's first term. The Obama administration is also attempting to overhaul the nation's health-care system and regulate greenhouse-gas emissions.

With GM's rise out of bankruptcy protection, the U.S. government for the first time owns a giant industrial company, after taking a smaller ownership stake in Chrysler Group LLC. Obama has repeatedly said he doesn't want to run the companies and will seek to sell the government's stakes as soon as it appears "practicable," though his administration acknowledges that could take years.

Obama's handling of GM has already invited Republican criticism that he harbors a far-left, big-government agenda. But Alex Keyssar, a professor of history and social policy at Harvard University's John F. Kennedy School of Government, believes most Americans view the administration's GM takeover as a matter of necessity rather than an example of a broader agenda.

"It's an experiment that they were forced into," Keyssar said, noting that Obama faced the prospect of two large auto makers collapsing in his first months in office. "Anybody in office prays that they won't have to face that kind of situation."

GM emerged from reorganization faster than expected, a remarkable short-term achievement for the young administration. During the process Obama came under heavy criticism from creditors, dealers and other stakeholders who contended they were treated unfairly. But the swiftness of GM's and Chrysler's reorganizations could validate the administration's dealings with the companies.

Still, final judgment of the administration's auto restructuring will ultimately hinge on the long-term success of the auto makers.

Clifford Winston, a senior fellow at the Brookings Institution, a Washington think tank, warned that while the administration may have prevented GM from a sudden collapse, the restructuring has yet to address a central cause of the auto maker's problems.

"In terms of daily operations, nothing is fundamentally changed," said Wintson, who has argued against a government bailout of GM. "We truly don't understand what inside the organization enabled the decline to go unchecked for so long. They'll point to legacy costs. That's very recent."

He predicted that GM would continue to lose market share to foreign rivals because the restructuring hasn't ensured that the company will improve its products.

"I see a company still in trouble," he said.

-By Josh Mitchell, Dow Jones Newswires; 202-862-6637; joshua.mitchell@dowjones.com