The Campaign for Primary Accountability, a super PAC that bills itself as nonpartisan and was instrumental in ousting  incumbent Republican Reps. Jean Schmidt (Ohio) and Don Manzullo (Ill.), has raised nearly all of its $2.5 million from donors who have supported Republican candidates and the GOP party committees the group claims to be working against.

The political action committee’s recent decision to hire Mark Meckler, a high-profile tea party activist, raises further questions about its independence. Officials at the Tea Party Express, a California-based PAC, and FreedomWorks, a conservative grass-roots group that has claimed the tea party mantle, have questioned what’s driving  the CPA’s agenda.

The super PAC, launched last November, has spent more than $1.5 million in 14 primaries so far this year, quickly building a reputation as an anti-establishment powerhouse.

It is driven financially and strategically by conservative operatives and has had little luck pulling Democrats and liberals into its fold, according to a Roll Call analysis of the PAC’s 48 largest donors, who gave $250 or more through the end of March.

Meckler, a former work-from-home Internet lawyer, earned $150,000 a year as the co-founder of the Tea Party Patriots. He developed a reputation as a prolific fundraiser, helping the group secure its first $1 million donation, which opened the floodgates for $12.2 million in small contributions from May 2010 to May 2011.

In February, Meckler left Tea Party Patriots to join the CPA as an adviser on grass-roots strategy and to lead an affiliated nonprofit, Citizens for Self Governance. The alliance could help the CPA tap into small-dollar tea party donors.

“I call it the citizen super PAC,” Meckler said in an interview.

To date, the PAC has relied on donors who have given tens of thousands of dollars to the Republican National Committee, National Republican Congressional Committee and National Republican Senatorial Committee, all of which help bankroll  incumbents trying to defend their seats.

Dean White, an Indiana billionaire who gave $25,000 to the CPA, also cut $30,000 checks each to the RNC and NRCC this cycle, according to federal records. White declined to comment for this story.

The CPA’s donors include supporters of presumptive Republican presidential nominee Mitt Romney and Sens. John McCain (Ariz.) and Dick Lugar (Ind.), whose primary loss last week has become emblematic of anti-incumbent fervor.

Nearly all of the CPA’s donors have given money to Republican candidates or party committees at some point since the 2008 cycle, records show.

A handful of the super PAC’s supporters have made small donations to two Texas Democrats: Former Houston Mayor Bill White, who ran for governor in 2010, and Beto O’Rourke, who is hoping to unseat Rep. Silvestre Reyes (D-Texas) this year. The CPA has spent $50,000 on advertisements opposing Reyes, an eight-term moderate Democrat facing a primary challenge on May 29.

Eric Pulaski, the CEO of a Texas-based online storage company Smart Vault, contributed $1,000 to the CPA. He supported Barack Obama in 2008 and made a $25,000 contribution to the Democratic National Committee that same year. Pulaski did not return Roll Call’s request for comment.

Curtis Ellis, a spokesman for the CPA, said the group is not trying to shift the balance of power in Congress. “Our donors share our mission of defeating long-term incumbents and restoring competitive elections,” he said. “Their money is used to work on both sides of the aisle.”

Leo Linbeck III, the Republican son of a Houston construction magnate, hatched the idea for the PAC in the summer of 2010. He initially focused efforts on a campaign to assert the state’s authority to regulate medical care in the aftermath of the 2010 U.S. health care overhaul.

 Linbeck met Meckler while peddling the idea at a Tea Party Patriot’s conference. When Meckler decided to leave the Patriots, Linbeck asked him to run Citizens for Self Governance, a charitable nonprofit he established in 2010.

Citizens for Self Governance raised just more than $1 million in 2010, according to its most-recent IRS filings, but has been largely dormant in the past year. Meckler says he’s started to revitalize the nonprofit, focusing on issues “where the division between liberals and conservatives is not relevant,” such as switching voting from Tuesday to Saturday and criminal justice reform.

The nonprofit, along with a second social welfare organization called the Alliance for Self-Governance, could allow Linbeck and his allies to tap another new pool of donors — those who do not want to be publicly associated with the PAC.

Political action committees often have tax-exempt arms. However, the nonprofits, which are not required to disclose their donors, could present a liability as the CPA tries to establish its anti-
establishment bona fides.

The CPA’s moves have puzzled activists on the political right and left, who also see themselves as part of the anti-establishment tide and aren’t sure whether the group is an ally.

“The problem for us is that they are all over the map,” said Russ Walker, the national political director at FreedomWorks, which was founded by former House Majority Leader Dick Armey (Texas). “Not every incumbent is created equal; you can’t just eject someone because they have been there for a while.”

FreedomWorks defended Manzullo, a fiscal and social conservative.

The CPA has reached out to progressive groups, including NOW DC, an Occupy Wall Street-inspired organization based in Washington, D.C.

“I didn’t really want any part of the PAC,’’ said Kevin Zeese, one of NOW DC’s leaders. “No matter who is elected, we’re going to have to force them to follow the people’s interests.”