More than 25 percent of House Members serving their first full term in Congress have already set up their own political action committees, making the term “leadership PAC” a bit of a misnomer.

New Senators are also jumping into the fray. For instance, freshman Sen. Mike Lee (R-Utah) opened Lead Encourage Elect PAC in mid-March and then opened another leadership PAC, the Constitutional Conservatives Fund, in early June.

Lee is one of 70 Members in both chambers who are seeking to reap the rewards of these auxiliary fundraising vehicles during their first full term.

Overall, 373 Members of Congress have filed paperwork for leadership PACs, which is almost 70 percent of all federal lawmakers. Since 2000, the number of leadership PACs — including those connected to candidates and former lawmakers — has more than doubled, according to a CQ MoneyLine study.

“If the conventional wisdom is that every Member of Congress has a leadership PAC, that’s obviously not true,” said Caleb Burns, a partner at Wiley Rein in the firm’s election law and government ethics section. “But it sounds like the vast majority of them do.”

The financial advantages of having a leadership PAC are quite clear. During the 2010 election cycle, the average leadership PAC brought in $285,000.

Republicans making the most of these groups this year include Sen. Jim DeMint (R-S.C.), who has taken in more than
$2.5 million with his Senate Conservatives Fund, and House Majority Leader Eric Cantor (R-Va.), who raised more than $1.5 million through his Every Republican Is Crucial (ERIC) PAC.

Democrats with large leadership PAC receipts in 2011 include Sen. Harry Reid (Nev.) raising $608,000 through his Searchlight Leadership Fund, Rep. James Clyburn (S.C.) raising $569,000 with Bridge PAC, and Sen. Barbara Boxer (Calif.) taking in $538,000 with her group, PAC for a Change.

While Members cannot use this money for their own races, they often dole out these funds to other federal candidates, as well as to Democratic and Republican party committees in an effort to increase party building. The PACs also allow Members to funnel money to state and local candidates, boosting their own support and increasing turnout for their elections.

Campaign finance reform advocates have long criticized leadership PACs as being “slush funds” for lawmakers. They argue that large donors use leadership PACs to gain more influence and give more money to Members of Congress than they can give to their campaigns.

Politically, more than 71 percent of Democratic lawmakers have leadership PACs, which narrowly edges out the 67 percent controlled by Republican Members. Most of the lawmakers without leadership PACs serve in the House.

The Senate has only five lawmakers without leadership PACs listed at the Federal Election Commission: Sens. Jeff Bingaman (D-N.M.), Maria Cantwell (D-Wash.), Herb Kohl (D-Wis.), Carl Levin (D-Mich.) and Olympia Snowe (R-Maine).

While new Members have rushed to start PACs, some long-serving Members have declined to do so. For instance, neither 20-term Rep. Pete Stark (D-Calif.) nor Rep. Barney Frank, ranking member on the House Financial Services Committee, has a leadership PAC.

Stark is one of the most senior Members without a leadership PAC after being first elected to Congress in 1972, before the FEC was created. Frank, meanwhile, described leadership PACs as an unnecessary burden.

“I wish I didn’t have to do any fundraising at all,” said the 16-term Massachusetts Democrat, explaining why he does not have a leadership PAC. “But I do attend fundraisers to help raise money for the [Democratic Congressional Campaign Committee] and many of my colleagues.”

For more than a decade, it was unknown how many Members had leadership PACs because the FEC did not require federal lawmakers to disclosure their connections to PACs until 2009. Even then, some Members of Congress were slow to send in the required forms detailing those connections.

As of the end of September, several Members of Congress failed to file new statements of organization linking themselves to their leadership PACs as required under FEC rules. Many of the campaigns and Congressional offices contacted by Roll Call explained that the missing forms were an oversight that they planned to fix.

“The PAC was started before the related paperwork included an option to declare it as a leadership PAC,” said Jonathon Dworkin, spokesman for Rep. James Langevin (D-R.I.), who operates a leadership PAC called Ocean State PAC. “The Congressman has reported all of its activity as required since it began and is also updating the original paperwork with a new form to show it is a leadership PAC.”

While the new filing is just an amendment, some Washington watchdog groups say it is critical that Members identify their PACs.

“I think it is more than a trivial matter,” said Paul S. Ryan, a lawyer at the Campaign Legal Center who works on election law issues. “The public has no way of knowing that a Member of Congress has a second pot of money because that Member of Congress failed to fill out the paperwork.”