The political credibility of some prominent Tea Party groups is being questioned in the wake of revelations that their star Senate candidate, Kentucky businessman Matt Bevin, supported the 2008 government bailout of the financial sector.

Bevin is challenging Senate Minority Leader Mitch McConnell in Kentucky's May 20 Republican primary, and has made the incumbent's support for the Troubled Asset Relief Program a central theme of a campaign attacking McConnell as insufficiently conservative. Bevin's Tea Party supporters have joined in, criticizing McConnell for negotiating TARP while touting the Louisville financier as a true conservative who opposed the program six years ago and would do so again.

Except that Bevin did not oppose TARP in 2008. According to a signed report his firm compiled for investors, Bevin praised the program and said it was a positive step for the economy, which at the time was in free-fall as stock and home values plummeted. The story was first reported by Politico. Bevin has attempted to distance himself, denying that the statements he signed for the investor report equaled support for TARP.

Bevin’s rhetorical maneuvering is standard procedure for any candidate caught in such a glaring contradiction. But it’s just this sort of political jujitsu that Tea Party activists typically deride as unprincipled. Still, Bevin’s supporters — including the Senate Conservatives Fund and Madison Project, both based in Washington — are sticking by him, dismissing the TARP revelations as a desperate, McConnell-orchestrated attack. The organizations have hardly been as charitable with establishment Republicans.

McConnell partisans and some Tea Party-aligned conservatives charge that the groups are looking the other way because their decision to support Bevin was never about replacing McConnell with a more committed conservative. Rather, it was about the public relations, fundraising and notoriety that came with challenging one of the most powerful Republicans in Washington. That Bevin might be less conservative than advertised was irrelevant.

“I think they want to make an example out of McConnell if they can,” said a veteran Republican operative who is based in Washington. “But bigger still, they are getting media hits for going after McConnell, which equates to profile and dollars.”

In a column posted Monday, Tea Party Nation founder Judson Phillips was similarly critical. Judson wrote that McConnell is flawed and deserves a primary challenge. But he said that the Kentuckian's conservative opponents, whom he described as the “conservative establishment,” are backing Bevin for reasons that smack of politics, as opposed to the ideology that drives the Tea Party. Otherwise, Phillip said, they would take on other Republicans with more “liberal” voting records than McConnell.

“McConnell has offended conservatives by stabbing Ted Cruz in the back and cutting deals that ran contrary to every principle he says he stands for. The Conservative Establishment is backing unknown Matt Bevin. Bevin has no track record. McConnell has a Heritage Action rating of 80. When the average Republican score is 67 that is not something to ignore,” Phillips said.

McConnell scored even better with the Club for Growth, nabbing an 87 percent rating on the free market group's issues. This cycle, the club has endorsed Republicans who are challenging incumbents in Senate primaries, but Bevin is not among them. Sen. Rand Paul, R-Ky., a strong supporter of McConnell who has criticized Bevin, was at 96 percent on the Heritage Action for America scorecard. Bevin has never served in elected office.

In fall 2008, McConnell and other Republican leaders worked with President George W. Bush to muscle TARP through a Democratic-controlled Congress, over the objections of some conservatives. Soon after TARP passed, the financial markets stabilized, and the economy, though mired in a deep recession, never fell into a depression. The unpopular program was deemed successful.

But the Wall Street bailout was difficult for conservatives to stomach, and to some degree the political cloud it cast over Republicans remains. For some conservatives who aligned with the Tea Party, McConnell had never been combative enough for their taste. Their dissatisfaction with him finally boiled over in October when he opposed the campaign led by Sens. Ted Cruz, R-Texas, and Mike Lee, R-Utah, to defund Obamacare through the budgetary process.

McConnell killed the defunding movement in the Senate and helped negotiate an end to the 16-day government shutdown. The Senate Conservatives Fund, which bankrolled the defund-or-shutdown media campaign, endorsed Bevin soon after. McConnell then signaled to Republican consultants that anyone doing business with the fund would be blacklisted from GOP campaigns. Some Republicans say the McConnell-Bevin primary is a personal grudge match between the conservative and GOP establishments, and a proxy war for power over the party.

The groups supporting Bevin argue otherwise. In email exchanges with the Washington Examiner, the Senate Conservatives Fund and the Madison Project vigorously defended Bevin’s personal integrity and conservative credentials. They denied accusations that they targeted McConnell, and continue to invest in Bevin, in an attempt to garner political power, gain attention or raise money.

“Between McConnell and Bevin, McConnell was the only one with the opportunity to prevent TARP from becoming a reality, and he enthusiastically voted for it and convinced others to follow,” Madison Project spokesman Daniel Horowitz said.

"There is certainly much to dislike about Mitch McConnell, but we're supporting Matt Bevin because he's a principled conservative,” added Matt Hoskins, who runs Senate Conservatives Fund. “McConnell can't win on the issues, so he's attacking Bevin's character.”

McConnell's supporters charge that such statements are laughable. To make their point, they pointed to the past record of the Senate Conservatives Fund, established by Heritage Foundation President Jim DeMint when he was a South Carolina senator.

DeMint would occasionally butt heads with Senate GOP leaders over the candidates his political action committee backed. But the disagreement usually centered on political tactics, candidate quality and electability in a particular state. Few argued that the candidates DeMint backed were anything but the kind of principled, stalwart conservatives he touted them to be. With Bevin, all of that has changed, establishment Republicans contend.

The Senate Conservatives Fund, said a Republican operative backing McConnell, is making the same mistake with Bevin that the National Republican Senatorial Committee made in 2009 with Charlie Crist. In 2009, the NRSC hastily endorsed then-Republican Gov. Crist over Marco Rubio, who had the backing of DeMint. Rubio won the 2010 GOP primary and was elected senator. Crist left the GOP in the middle of that campaign and this year is running for his old job as a Democrat.

“Being pure is not particularly difficult but it is essential to hold the high ground when smearing others as squishes. They have lost that [credibility] entirely with this race,” the GOP operative said. “That stain does not come out … It's like the NRSC endorsing Charlie Crist. It leaves a lasting impression whether that's fair or not.”