DETROIT  The rapidly deteriorating finances of General Motors are forcing the federal government to decide whether to bail out the largest American automaker or face the prospect that it might go bankrupt.

G.M. said Friday that its cash cushion had been dwindling by more than $2 billion a month recently and that it could run short of money by mid-2009 unless it got emergency federal assistance.

It also said it had suspended merger talks with Chrysler to focus on its own increasingly urgent problems, brought on by higher gas prices, a weakening economy and tight credit  a combination afflicting the entire auto industry, but hurting G.M. the most.

The government faces a difficult choice. If it provides G.M. with a bailout, there is no guarantee the company will not need more money later to stay out of bankruptcy, particularly with the economy weakening.