Moreover, the Fed is exposing itself to the risk that the assets it has purchased, like the $1 trillion in mortgage-related securities on its balance sheets, could shrivel in value as interest rates rise. That could reduce the amount of money the central banks turns over to the Treasury each year, and expose the Fed — which has been attacked for failing to prevent the 2008 financial crisis — to further criticism.

And then there is a risk that the Fed’s action could be neutralized by a new Congress that has vowed to contract government spending, a core argument that led to the overwhelming Republican victory on Tuesday.

Mr. Obama, at a news conference on Wednesday, talked of compromise with the new Republican majority in the House. But he also cited China’s new high-speed trains and its advances in supercomputing to make the case that there are some areas where the United States needs to make investments, and insisted that the country would not shy away from those. “They are making investments, because they know those investments will pay off in the long term,” he said of the Chinese, seeming to suggest that the United States needs to do the same.

At the same moment, he reiterated that he would support continuing the Bush era tax cuts only for families earning less than $250,000 a year. “It is very important we’re not taking money out of the system from people who are most likely to spend that money,” Mr. Obama said at the news conference.

But he hinted at flexibility, saying he expected to sit down with the new Republican leadership to see “where we can move forward first of all in ways that can do no harm.”

Asked if he was willing to negotiate, he said, “Absolutely.”

Laurence H. Meyer, a former Fed governor who closely monitors the central bank, said the prospect of sustained fiscal gridlock had already pushed Mr. Bernanke to move.

“Bernanke has said that fiscal stimulus, accommodated by the Fed, is the single most powerful action the government can take for lowering the unemployment rate ,when short-term rates are already at zero,” Mr. Meyer said. “He has nearly pleaded with Congress for fiscal stimulus, but he can’t count on it. So he has to act as if that’s not going to happen. “