Sens. John McCain (R-Ariz.) and Russ Feingold (D-Wis.) are putting their band of reformers back together and hitting the halls of Capitol Hill in pursuit of their latest mission — curtailing the practice of earmarking federal dollars in legislation, sources said late last week.

The most prominent campaign mounted by the reforming duo resulted in passage of a massive package of campaign finance reform measures in 2002.

The Bipartisan Campaign Reform Act, popularly known as McCain-Feingold, won the two lawmakers a following among journalists and government watchdog groups, but did little to endear them to the old-line institutionalists within their parties — including, most notably, Senate Minority Leader Mitch McConnell (R-Ky.), who led the opposition to the bill.

Feingold’s office confirmed that the two are exploring a reunion of sorts starting in the 111th Congress that would attempt to duplicate in the earmarking fight the success they had with campaign finance.

“Our offices have been in touch about continuing to work together on earmark reform. … Sen. Feingold and Sen. McCain have a long history on reform issues including earmark reform. Back in 2006, Sen. Feingold joined Sen. McCain in introducing the Pork-Barrel Reduction Act,” a Feingold aide said.

Republicans and Democrats alike said they were not surprised the two lawmakers would take on earmarks.

“It’s not surprising. That’s always been his thing,” a GOP leadership aide said of McCain.

A senior Democratic leadership agreed. “I’m not shocked,” this aide said, adding that Senate Majority Leader Harry Reid (D-Nev.) expected earmark reform to be on the agenda “whether we wanted it to be or not.”

McCain has long been a leader of his party’s fiscally conservative wing that has sought to rein in the earmarking practice, and he has often run afoul of GOP “Old Bulls” such as outgoing Sen. Ted Stevens (R-Alaska) for his strong criticism of earmarked projects.

McCain also made earmarks a central plank of his presidential campaign and made repeated references to the issue in stump speeches and debates. Indeed, he credited Alaska Gov. Sarah Palin’s (R) image as an earmark reformer as one of the central reasons he tapped her as his vice presidential running mate.

Similarly, Feingold has a long history of pushing for reforms in the Senate. But unlike McCain — who found a natural constituency among his party’s fiscal hawks — Feingold was often the sole Democratic advocate for controls on earmarking until President-elect Barack Obama arrived in the Senate in 2004 and Sen. Claire McCaskill (Mo.) was elected in 2006.

Unlike their years-long efforts on campaign finance reform, McCain and Feingold could find the going much easier on earmarks, thanks to changes in the political climate in Washington.

For instance, the Jack Abramoff lobbying scandal, federal investigations into Stevens’ use of earmarks and other scandals involving the earmarking process have significantly tarred the practice in the public’s eye. Obama made earmark reform one of the main parts of his ethics reform efforts while in the Senate and he has indicated he will look to curtail the practice as president.

Additionally, with McCaskill and other reform-minded Democrats joining the House and Senate in recent years, combined with the greater influence GOP fiscal hawks will have within their reduced Conference, Republicans and Democrats said the time could be ripe for significant reform.

John Hart, a spokesman for Sen. Tom Coburn (R-Okla.), said his boss “hopes to work with Sens. McCain, Feingold and anyone else who recognizes that earmarks are a terrible way to allocate taxpayer dollars. Republicans and Democrats have a real chance to work together and help President-elect Obama end the practice of using earmarks as a governing strategy.” Coburn has been a vociferous advocate of earmark reform and a close McCain ally.

“They have an opportunity to put through something that is rational and makes sense for everyone. It’s an issue that has become divisive and it doesn’t need to,” a senior GOP Senate aide said, noting that McConnell last year embraced earmark reform efforts in his own Conference and attempted to push through a modest set of changes.

“McConnell is not someone who is ideologically opposed to earmark reform,” this aide said.

McCain and Feingold could run into parochial resistance, particularly if they look to move the authority for policing earmarks out of Congress, as many reformers have called for.

“The question that remains for McConnell and others … is whether you cede Congressional authority to direct dollars back to your state,” the senior aide explained, adding that while some hard-line conservatives such Sen. Jim DeMint (R-S.C.) may favor allowing the administration to police earmarks, many Republicans won’t.

“You’d like to think that Jim DeMint has a better idea of the priorities of South Carolina than President Obama, but that remains to be seen,” the aide said.