Many believe this form of hybrid ownership — part government, part private, with the responsibilities of ownership unclear — will not prove workable.

“The case for full nationalization is far stronger now than it was a few months ago,” said Adam S. Posen, the deputy director of the Peterson Institute for International Economics. “If you don’t own the majority, you don’t get to fire the management, to wipe out the shareholders, to declare that you are just going to take the losses and start over. It’s the mistake the Japanese made in the ’90s.”

“I would guess that sometime in the next few weeks, President Obama and Tim Geithner,” he said, referring to the nominee for Treasury secretary, “will have to come out and say, ‘It’s much worse than we thought,’ and just bite the bullet.”