Controlling the federal purse strings in Washington, D.C., has been a time-honored way for powerful lawmakers to curry favor at home and secure re-election year after year.

But this year, three powerful Democratic chairmen — Budget Chairman John Spratt (S.C.), Appropriations Chairman David Obey (Wis.) and Armed Services Chairman Ike Skelton (Mo.) — face tough races as a surging GOP looks to use the lawmakers’ power against them and turn them into electoral trophies.

The Democratic trio also will take center stage during what remains of the House’s legislative agenda. Spratt has been struggling to negotiate a budget resolution with House leadership, Obey, liberals and fiscally conservative Blue Dogs. Obey faces the perennial challenge of pushing through spending bills. This year, the Appropriations chairman’s job is even further complicated by an earmark moratorium imposed by the Republican Conference, which has made Democratic spending a centerpiece of its strategy to take back the House. Skelton, meanwhile, will be in the middle of the upcoming House debate over President Barack Obama’s Iraq and Afghanistan policies.

Indeed, the national political mood and a sense of legislative exhaustion following the marathon health care debate has the House leadership seriously considering ditching a budget for the first time since the modern budget process was enacted in 1974.

The National Republican Congressional Committee is already making the case against Spratt and Obey, running ads against both calling them architects of the Democratic agenda.

“Spratt is Nancy Pelosi’s budget chairman, and the Spratt budget has a trillion-dollar deficit,” says a narrator in a spot the NRCC cut in January that ran on cable in South Carolina for a week. “And Spratt’s the architect of legislation Democrats may use to ram through a government takeover of health care.” The NRCC’s Obey ad, which also ran on cable in his district last month, called the Wisconsin Democrat “the architect of Obama’s spending.”

“Obey chairs the Appropriations Committee,” the narrator says. “Obama’s spending gets Obey’s stamp of approval. It’s a Niagara Falls of money flowing out of Washington.”

Tom Kahn, Spratt’s chief of staff on the Budget Committee, said Democrats hope to decide in the next few days whether to do a budget this year.

“There are upsides and downsides to doing a budget, particularly this year. But from a procedural standpoint, reconciliation is the only major tool we would not be able to use” by not doing a budget.

The new pay-as-you-go budget law also makes it easier for Spratt if a budget isn’t passed. “It laid out not just a blueprint but enforceable limitations,” Kahn said. “It’s pretty tough medicine.”

Spratt also could be insulated by his prominent spot on the president’s bipartisan deficit commission and his role as the second-ranking member of the Armed Services Committee under Skelton.

Of the three Democratic chairmen, Democratic strategists believe Skelton is best positioned to weather the 2010 cycle. While he voted with the party on last year’s stimulus bill and climate change package, he opposed the health care overhaul. And he is poised to buck the party again later this month by opposing a repeal of the “don’t ask, don’t tell” law that bans openly gay people from serving in the military — one of the more contentious debates that could complicate passage of a Defense authorization bill that the Missouri Democrat will manage.

And Skelton has been hustling to stock his campaign war chest, raising more than $1 million in the first quarter to report more than $1.2 million in cash on hand. Obey has banked $1.4 million, and Spratt has more than $800,000.

Chairmen are usually among the safest incumbents. In an institution that rewards seniority, most have proved to be survivors by hanging around long enough to get a gavel in the first place. And once installed at a panel’s helm, the lawmaker can boast back home of enhanced ability to deliver federal largess.

But there have been cases of modern wave elections wiping out once-sturdy chairmen and leaders. In those years, the soured political environment turns what had been an asset — the power to set the agenda — into a liability.

“Senior Democrats such as Obey, Spratt and Skelton are vulnerable this cycle, in part, because of their positions of power in the House and their roles in advancing their party’s legislative agenda,” said Stuart Rothenberg, a contributing writer for Roll Call who also authors the Rothenberg Political Report. “Voters are angry, and they are looking for someone to take their anger out on.”

In the 1980 elections, Republican candidates rode Ronald Reagan’s coattails and an anti-incumbent mood to capture 33 Democratic House seats. Among those knocked off was Ways and Means Chairman Al Ullman (D-Ore.), whom his Republican challenger successfully painted as having lost touch with his constituents after 24 years in office. And Republican John Hiler defeated then-House Majority Whip John Brademas (D-Ind.) by portraying the leader as a major force behind a failed Democratic economic program.

The 1994 midterms, in which Democrats lost 53 House seats and control of the chamber, saw Republican George Nethercutt pull off a stunning upset by beating then-Speaker Tom Foley (D-Wash.). And Republican Steve Stockman unseated Judiciary Chairman Jack Brooks (D-Texas) by tarring him for his support of a pork-laden crime bill that included gun-control provisions. Former Ways and Means Chairman Dan Rostenkowski (D-Ill.) lost re-election that year, too. And though Rostenkowski’s defeat was a surprise, his star had been waning rapidly since a 17-count indictment on charges of embezzlement and fraud that forced him to surrender the gavel of the tax-writing panel.