He said that left the Obama administration to decide whether to allow “a laissez-faire, uncontrolled bankruptcy, which would have had an enormous cost,” or a “controlled process,” in which the goal was to make sure that the auto companies not only restructured, but were not overburdened with debt. So, in return for what amounted to debtor-in-possession financing, Mr. Obama chose to accept equity in the new company  while insisting that he had no intention of exercising day-to-day control over the company.

“It’s a fine line,” Mr. Summers said, “but we think it is manageable.”

To assist in the restructuring, the automaker is expected to hire the consulting firm Alix Partners, which has worked on several major bankruptcies, including those for Enron and Kmart. One of the firm’s partners, Al Koch, is expected to manage the liquidation of corporate assets that G.M. will shed during its Chapter 11 restructuring, people with knowledge of the strategy said.

Mr. Obama is taking several risks under the plan. None may be bigger than the decision that the United States government will take its 60 percent share of the stock in a new G.M., leaving taxpayers vulnerable if the overhaul is not successful. (Canada, for its part, is taking a 12 percent stake.)

“We don’t think that after this next $30 billion, they will need more money,” one administration official said. “But the fact is there are things you don’t know  like when the car market will come back, and how much Toyota and Honda and Volkswagen will benefit from the chaos.”

On Monday, Mr. Obama is expected to argue that any alternative to his plan would be worse, and that a liquidation of G.M.  the only other real option  would send the unemployment rate soaring over 10 percent and would radiate damage throughout the economy.

But aware of the hardships the plan will impose on regions across the country that depend on auto production, the White House is dispatching a dozen Cabinet members and other officials across four states this week to reassure residents.

Aides say Mr. Obama will portray himself on Monday as a reluctant shareholder, eager to sell the company back to private investors, perhaps within 6 to 18 months.