“A body of 535 doesn’t sing easily in one chorus,” said Senator Lamar Alexander, Republican of Tennessee. “I would get up in the morning, look in the mirror and say three words: ‘the Obama economy,’ ” he said, “Then say, ‘They’ve been in charge, they made it worse, we can make it better.’ And remember all three messages.”

Defense is not a position that House Republicans of the 112th Congress are accustomed to playing. The group had remarkable leverage last year, setting the agenda on spending — reining it in beyond what even Mr. Boehner would have dreamed — and beating back Democrats on a variety of policy areas in the process.

But the public audience was not always wowed by their accomplishments. Polls showed that many Americans, even those who agreed with the Republican fiscal agenda, found the process, which included nearly shutting down the government, too messy. And among hard-core conservatives, the Republican gains were often too slight to win them applause.

At their retreat in January, Republicans tried to get back on the same page. They are now trying hard to demonstrate where they agree with Democrats, like in the area of small business, while still hammering away at Mr. Obama on unemployment and energy policy, subjects they think resonate with voters.

Should the Supreme Court find fault with some or all of the health care law, Republicans will be ready with a replacement, they say, and will push a bill banning stock trades by lawmakers and staff members with conflicts of financial interests.

House and Senate negotiators are already locked in talks to extend the payroll tax cut through the rest of the year, as well as to extend unemployment compensation and stop a deep cut in payments to doctors treating Medicare patients.

“We’ve had a lot of positive discussions about the year ahead,” said Kevin Smith, a spokesman for Mr. Boehner, “and our members are united against the president’s policies, which are making the economy worse, and united in our efforts to offer better solutions to help middle-class families and small businesses.”