The issue reignited speculation, common in the administration’s early months, that Mr. Geithner and perhaps Lawrence H. Summers, the senior White House economic adviser, were not long for the Obama world given broad public perceptions that they remained too close to the financial industry.

But numerous administration officials said that both men had earned the trust and confidence of Mr. Obama, who believed they had not received credit for stabilizing a financial system that by all accounts was on the verge of collapse when the president took office.

His pique on that score came through in his televised interview with ABC News on Wednesday, after the loss in Massachusetts, even as Mr. Obama empathized with Americans’ anger about the bailout effort, the Troubled Asset Relief Program, that he inherited from George W. Bush.

“Now if I tell them, ‘Well, it turns out that we will actually have gotten TARP paid back and that we’re going to make sure that a fee’s imposed on the big banks so that this thing will cost the taxpayers not a dime,’ that’s helpful,” Mr. Obama said. “But it doesn’t eliminate the sense that their voices aren’t heard and that institutions are betraying them.”

To change that, he added, “We’re about to get into a big fight with the banks.”

That fight is sure to continue testing Mr. Geithner, as well as Mr. Summers and lesser-known members of the economic team who are seen by others in the West Wing as politically tone-deaf. Yet Mr. Geithner, in an interview, said he foresaw no problems.

“Just because things seem populist doesn’t mean they’re not the right thing to do,” he said.

The administration’s new tack suggests just how much big banks have miscalculated Americans’ intensified resentment against the bailout  anger stoked by persistent high unemployment, banks’ stinginess in lending to small business and the revival of Wall Street’s bonus culture.

They have become the perfect foil for the White House as it tries to lead the Democratic Party out of its post-Massachusetts morass  and to change the channel from the seemingly unending debate over health insurance. As the White House hopes to define the fight, the enemy is not big government but big money.