With Rep. Marty Meehan (D-Mass.) stepping down within weeks and no obvious Democratic heir apparent on campaign finance matters in sight, reform groups are bracing themselves for the soon-to-be bygone era of one-stop shopping within the House’s majority party.

“I don’t expect anyone to be as dynamic as Marty Meehan for a while yet because they have to learn this subject … Marty Meehan has been in the trenches for years,” said Craig Holman, a lobbyist for Public Citizen’s Congress Watch. “Marty Meehan is not only firmly committed to sweeping campaign finance and ethics reforms, but he’s also an expert in the field.”

“It’s going to be a big blow … I’m not looking forward to this,” Holman added.

Meehan will step down on July 1 to become the chancellor for University of Massachusetts-Lowell, his alma mater. Meehan was unopposed in November’s midterm elections, when he won his eighth term. An Oct. 16 special election has been scheduled to replace him.

Since arriving in Washington, D.C., in 1991, Meehan has been the House’s go-to Democratic campaign finance expert. During his tenure, he frequently has joined Rep. Christopher Shays (R-Conn.) in sponsoring marquee reform measures; the underlying House version of 2002’s Bipartisan Campaign Finance Reform Act — commonly referred to as McCain-Feingold, for its Senate sponsors — is called Shays-Meehan.

Shays suggested in an e-mail Monday that he will look to multiple Democrats to fill the Democratic vacuum on campaign finance reform issues.

“Congressman Meehan and I have worked closely with a number of other Members over the years and I am looking forward to continuing to do so,” Shays wrote.

Of the 20 campaign finance related bills proposed in the House during the 110th Congress, Meehan is the primary sponsor of two bills that reform groups hope to hang their hats on this Congress: salvaging the presidential public financing system and cracking down on some political groups organized under section 527 of the federal tax code.

With Meehan’s departure, Fred Wertheimer, president of Democracy 21, said his group will now rely on a variety of House Members to shoulder his group’s priority issues though the Congress. On updating the presidential public financing system, Wertheimer said Democratic Reps. David Price (N.C.) and Chris Van Hollen (Md.) are expected to become increasingly vocal following Meehan’s exit.

“Certainly two people we would see as potential key players down the road on campaign finance reform,” Wertheimer said.

“If you look at Van Hollen’s leadership on the bundling issue and his role as a principal sponsor of the presidential public financing bill, he is certainly one person that we hope to see in a leadership role,” he continued.

Still, Wertheimer warned that “it’s early in the game” to anoint Van Hollen, Price and perhaps others as Democratic torchbearers in the House. Wertheimer, too, doubted Meehan’s replacement would be a single Democratic lawmaker.

While Van Hollen’s prominent role in the still-pending lobbying bill has many predicting he’ll step up his presence overall on campaign finance issues, one Democratic source said don’t bet on it. The source said that although Van Hollen is “reform minded,” he may take a piecemeal approach on the issues.

“A lot of this stuff is situational,” the source said. “He’s not looking to [take up] the mantle” from Meehan.

Price spokesman Paul Cox said his boss plans to pick up where Meehan left off on fixing the presidential public financing system. Price also already is working with Shays on soon-to-be introduced changes to independent expenditures, Cox said, and has co-sponsored legislation with Rep. Mike Castle (R-Del.) on robocalls and stand-by-your ad provisions for Internet communications.

Along with Rep. Todd Platts (R-Pa.), Castle also is named frequently as a Republican who may take up more campaign finance issues in Meehan’s absence. A Castle aide, however, said although Castle may become more active on campaign finance matters, Shays will continue to take the lead for the Republican Conference.

“Castle still going just as active, if not more, on these issues,” the aide said. “He’s not going to try and go crazy on his own.”

Because they’re looking to make good on Democratic campaign pledges to clean up Washington, D.C., Congress Watch’s Holman said a handful of freshman Democrats may see a rare opportunity to attach their names to frontline ethics issues.

“Reps. Tim Walz [D-Minn.], Jason Altmire [D-Pa.], Zack Space [D-Ohio], Baron Hill [D-Ind.] — these are some of the people I’m expecting are going to be very interested in pushing campaign finance reform and keeping it on the front burner,” Holman said.

A source said Democratic leadership is looking to Hill and Space, as well as Democratic Reps. Joe Sestak (Pa.), Christopher Carney (Pa.), Nancy Boyda (Kan.), Jerry McNerney (Calif.) and Nick Lampson (Texas), to take up campaign finance overhauls this Congress. All seven likely will face tough re-election challenges in 2008, which may hinge on whether they followed through on campaign promises — a potential liability for all freshman Democrats.

“As with many fellow members of the freshman class, I came to Washington, D.C., to change the way business is done,” Space said. “Any true ethics reform must include a comprehensive change in our campaign finance laws, and I know this class will lead that charge.”