As Congressional Republicans took yet another hit Tuesday with the defection of Sen. Arlen Specter (Pa.), debate kicked off about the role and influence of the conservative Club for Growth within the party.

The club’s reputation for knocking off moderate Republicans was thrust into the spotlight on Tuesday when Specter took parting digs at the group as he bid the Republican Party adieu.

“The Club For Growth challenged [former Rhode Island GOP Sen. Lincoln Chafee],— Specter said, after listing a host of club-opposed Republican casualties. “Remember Linc Chafee? They made him spend all his money in the primary and he lost the general.—

What’s more, Specter plainly admitted he became a Democrat because he could not defeat the outgoing head of the anti-tax group, former Rep. Pat Toomey (R-Pa.), in the GOP primary in 2010.

And while House Republicans expressed no remorse after Specter’s decision to abandon the GOP, many of his former colleagues agreed that the group’s tactics are increasingly corrosive to the party’s overall health and well-being.

“They are disgusting, I don’t admire Specter for what he did, but the Club for Growth is responsible for 12 former Republican seats now being held by Democrats,— Rep. Steven LaTourette (R-Ohio) said.

Rep. Fred Upton (Mich.), one of a dwindling number of GOP moderates in Congress, expressed concern that weeding out moderates would only hurt the party and its chances at ever taking back control of the House or the Senate.

“You know, to regain the majority you have to reach out to lots of different groups,— Upton said. “I know Arlen a little … but it hurts [the Republican Party] big time.—

Specter named several other former GOP Members, including Reps. Wayne Gilchrest (Md.), Joe Schwarz (Mich.) and Heather Wilson (N.M.) as casualties that resulted from the club’s interference. Democrats picked up Schwarz’s and Gilchrest’s seats after they were defeated in primaries by candidates backed by the Club for Growth.

Democrats also won Wilson’s seat when she left to run for Senate in 2008, but she was defeated in that primary by a more conservative club-backed Member. Last year Democrats also picked up a seat in Idaho, where club-backed former Rep. Bill Sali (R) — who by most all accounts ran a lackluster campaign — lost his re-election to now-Rep. Walt Minnick (D) in the conservative 1st district.

As a result, House Democrats have come to welcome the club’s involvement in any of their competitive races.

“Look, we encourage people to contribute to the Club for Growth,— Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.) said Wednesday, only half-jokingly. “I think that the results speak for themselves.—

National Republican Congressional Committee Chairman Pete Sessions (Texas), a Toomey ally during his primary against Specter in 2004, said the blame for unseating moderates should not be laid at the feet of the conservative group.

“They represent people who they know will oppose taxes and vote against [bills like] this budget,— he said. “Let’s not beat up the Club for Growth for standing for something.—

Sessions added that it was Specter alone who should bear the burden of his decision to switch parties.

The club’s incoming president, former Rep. Chris Chocola (R-Ind.), suggested the criticism was projected on the group as a result of other frustrations with the GOP. Chocola was defeated by Rep. Joe Donnelly (D-Ind.) in 2006.

“I think the criticism is misplaced and it may be trying to deflect some of the deeper problems, but ultimately it comes down to the voters’ choice,— Chocola said in a phone interview. “Arlen Specter said it himself.—

One Member, who requested anonymity in order to speak freely about correspondence with the Club for Growth, said that some House Republicans have tried to reach out to the group to “interject some reasonableness— into their decisions about which Members to target.

“There has been some useful dialogue with them about the wisdom of continuing to shrink the Republican Party,— said the Member.

Chocola said that Republican leadership had not reached out to him and that he maintains a good relationship with many of his former colleagues.

Rep. Peter Roskam (R-Ill.) said that in some cases the club has been successful in helping to bring new conservatives to the House, but he stressed that caution must be exercised when the club chooses which races to fund.

“There has got to be some discussion about the profile of certain districts,— he said.

Roskam added that the club also needed to provide some manner of fundraising support for its candidates instead of simply sending them an envelope full of money.

“You don’t have to build the fundraising base that you would if you were on your own [with Club for Growth support],— Roskam said. “If they helped get them here, they need to help keep them here.—

Schwarz — who lost the 2006 primary to club-backed candidate Tim Walberg, who went on to win the seat but get defeated in 2008 — said this lack of foresight was exactly what eventually landed the district in Democratic hands.

“I think the Club for Growth is financed by essentially the conservative plutocrats who don’t actually know what they’re getting their money into when they contribute to the Club for Growth,— Schwarz said. “These are not candidates who can win general elections.—

Created in 1999 by Stephen Moore, the club was formed to financially assist candidates who support its fiscally conservative platform that includes free trade, limited government spending and replacing the current tax code.

But not all moderates have an ax to grind with the club.

Rep. Mark Kirk (R-Ill.), who has gotten support from the group in the past, said he has confidence that new club President Chris Chocola has a firm grasp of how the current political environment has changed and will use the group’s influence wisely.

“He was in a pretty moderate district. He knows how the big issues have changed,— Kirk said.