?Uncle Needs a Diet,? declares the package assembled by Representative Jerry Lewis, Republican of California, one of three candidates in the race for one of the most powerful, and now paradoxical, jobs in government: leading the House Appropriations Committee in the new Congress as the Republican leadership tries to transform the panel from a fountain of federal spending into ground zero for budget cutting.

Selecting a chairman ? a party vote is expected Tuesday ? is the first step in perhaps the most audacious aspect of the plan by Representative John A. Boehner, the incoming Republican speaker, to alter the way the House works. Like Mr. Lewis, the other two leading candidates, Representatives Harold Rogers of Kentucky and Jack Kingston of Georgia, are campaigning to convince their party?s leadership that they can cast aside their own histories as earmarkers and pork-allocators and lead a shift in focus from how to spend it to how to save it.

To make the effort more than a slogan will mean upending one of the most entrenched cultures in Washington, a bipartisan tradition of directing money to favored causes with an eye as much to political gain as to policy outcome. Under both parties, the committee has long been a power unto itself, a secretive realm where subcommittee chairmen hold sway over Cabinet secretaries and generals and funding can almost magically materialize or disappear for little-scrutinized local projects even as national priorities are set or dismissed.

Leading the committee toward a belt-tightening mandate would also mean taking on an entire industry that has been built up around the federal trough, a complex of lobbyists, consultants and corporations who that feeds off the competition for dollars and with some regularity produces scandals ? and provides a substantial chunk of the campaign contributions that fuel the American political system.

?It has been a favor factory for years, and now it is going to become a slaughterhouse,? said Representative Jeff Flake, an Arizona Republican and longtime antagonist of the Appropriations Committee who is in line to be one of several antispending conservatives on the panel. ?It is going to get ugly.?

All the candidates for chairman have more than 15 years on the committee and all have hungrily sought earmarks. According to Taxpayers for Common Sense, in the last fiscal year, Mr. Lewis won 62 earmarks worth $97.6 million, followed by Mr. Rogers with 59 costing $93.4 million, and Mr. Kingston 40 worth $66.8 million.

Mr. Lewis was chairman of the committee before Democrats took control of the House in 2006 and would need a special exemption to be chairman again because of party-imposed term limits. In campaigning for the job, he has stressed his past efforts to push spending cuts. Mr. Rogers has emphasized his willingness to confront the executive branch on spending and his party fund-raising. Mr. Kingston has the backing of some outside fiscal watchdogs and pledges a new openness on the panel.

The team of Republican leaders planning to take over the House on Jan. 5 is exploring a variety of changes intended to break the committee?s spending mindset, starting with the new majority?s promise to slice $100 billion from President Obama?s budget request for the current fiscal year.

The three longtime committee members who aspire to head the panel have clearly gotten the message.

Like Mr. Lewis, his two rivals for the chairmanship – Mr. Rogers Mr. Kingston – are also committee members who have promised to devote themselves to paring spending, though all have funneled money to scores of projects through earmarks in past bills. The effort to reshape the committee promises to be a stern test of Republicans? rededication to fiscal sobriety after falling off the wagon during the dozen years, through 2006, that their party controlled the House, when government spending rose at rapid rates.

?They have promised things that they have neither delivered in the past nor, in my opinion, are going to be able to deliver on in the future,? said Representative Steny H. Hoyer of Maryland, the No. 2 House Democrat and a veteran of the Appropriations Committee himself.

To succeed and satisfy the conservative Tea Party-style voters that propelled them to power, Republicans will have to quickly make significant cuts in government programs and somehow find a way to enact those cuts into law in cooperation with a Democratically controlled Senate and a Democratic president.