House Democratic leaders might soon learn to be careful what they wish for.

Poised to extend their majority to more than 250 seats and with one of their own preparing to move into the White House, they now face competing pressures to deliver for their liberal wing without endangering their moderates by overreaching.

Their Republican counterparts are already beginning to struggle with how to recover from their Tuesday losses. The GOP setbacks claimed their first leadership casualty on Tuesday before the clock struck midnight, when Republican Conference Chairman Adam Putnam (Fla.) announced he would step down from his third-ranking slot.

Minority Leader John Boehner (R-Ohio) could announce a decision on his future as early as today, a source close to him said, and the fate of Minority Whip Roy Blunt (R-Mo.) remains uncertain.

Boehner congratulated President-elect Obama on his victory in a statement and said Republicans would hold Democrats accountable.

“We will rebuild our party the way it was originally built by President Lincoln and renewed nearly three decades ago by President Reagan: by fighting for the principles of freedom, opportunity, security, and individual liberty,” he said.

Conservative Republican Rep. Jeb Hensarling (Texas) is expected to officially seek the Conference chairmanship, according to GOP sources.

“Congressman Hensarling is likely to ask for Member support to run for Conference chair,” said an aide close to Hensarling, who has been the chairman of the conservative Republican Study Committee for two years.

If Hensarling gets the job, it would mark a significant rightward shift for the House leadership team. He has taken a far harder line against government spending and earmarks than Putnam and opposed the $700 billion bailout package backed by leadership.

Free of the shackles of partisan wrangling and leadership tussles, Putnam can set himself up for a run for statewide office in Florida, some GOP sources are speculating.

Democrats exulted in the spoils of victory and didn’t want to think — at least out loud to reporters — about their potential leadership races.

“I’ll think about that tomorrow; let me get through tonight,” Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.) said when asked if he was considering another term in the post or whether he would consider running for Caucus chairman if Rep. Rahm Emanuel (Ill.) is tapped for White House chief of staff.

If Emanuel goes, it opens up many possibilities for Members such as Van Hollen to consider a run at Emanuel’s Speaker-in-waiting status. But flush with their victory Tuesday night, potential contenders declined to speculate about any ladder-climbing.

“I’m not planning on being Speaker-in-waiting,” said Rep. Debbie Wasserman Schultz (D-Fla.), who is seen as a potential DCCC replacement for Van Hollen or perhaps even Caucus chairwoman. “I’m Debbie the hard worker. I’m ready to get down and roll up my sleeves,” she said.

Majority Leader Steny Hoyer (D-Md.) said he wanted his fellow Marylander to stay put for another cycle. “I think he did an excellent job, and I’d like to see him stay in it. 2010 is going to be a challenging year.”

Hoyer said he has not discussed a possible chief of staff position with Emanuel, although Hoyer said he would be “extraordinary” at it.

“It would be a very big hole to fill” if he were to leave, Hoyer said. “Obviously, the president will have to determine who he wants.”

Rahm drama aside, leaders face the challenge of managing liberal demands for increased spending and new programs with the fiscal conservatism of Blue Dog Democrats.

But it is not yet clear the Caucus fault lines will be so clearly drawn. Several Blue Dogs represent economically depressed districts that would likely benefit from new stimulus spending measures. And while they already wield significant influence by claiming about a fifth of the Caucus, their share of House Democrats isn’t poised to grow as a result of Tuesday’s elections.

The group lost at least three of its sitting members — Reps. Don Cazayoux (La.), Nick Lampson (Texas) and Tim Mahoney (Fla.) — while four Blue Dog-endorsed challengers came up short. Bobby Bright will join the group after winning in a Republican open-seat race in Alabama, as will Reps. Henry Cuellar (Texas) and Harry Mitchell (Ariz.). That means that as of early Wednesday morning, the coalition had yet to net any new members, with results in four of their challenger races still outstanding.

Nevertheless, earlier in the night, Rep. Dennis Cardoza (D-Calif.), a prominent Blue Dog and Pelosi confidant, said that given the nation’s economic straits, the group’s message of budget discipline will play a critical role in shaping policy.

“We don’t have enough money to do all the things we need to do,” he said. “What the American people voted for tonight was efficient, responsible government. We have to figure out how to deliver that. We can’t afford a penny more.”