Indiana Treasurer Richard Mourdock will kick off his campaign against Sen. Dick Lugar Tuesday, setting up the longtime Republican lawmaker for a potentially competitive primary. Mourdock told Roll Call that he will reveal a list of supporters that includes more than 75 percent of GOP county chairmen in the state.

Ted Ogle, chairman of both the Bartholomew County and 6th Congressional district Republican parties said he would be among the county chairmen endorsing Mourdock.

Mourdock said last week that he’s still trying to recruit county chairmen, so he would not disclose a specific number of endorsements, giving only the 75 percent figure. Ogle said Mourdock’s endorsement figure sounded right to him. Mourdock said his establishment support is a sign he is not running as an outsider.

“Certainly I expect Sen. Lugar’s campaign team to say I’m some tea party candidate and we’re charging the walls of the Republican fort, and in fact, it’s exactly the opposite,” Mourdock said in an interview.

Lugar senior adviser Mark Helmke dismissed Mourdock’s support but did not dispute the figure.

“Endorsements have not always translated into votes,” Helmke told Roll Call. He pointed to a 1996 Republican gubernatorial primary between Rex Early and Stephen Goldsmith, when he said Early had the support of a majority of county chairmen but Goldsmith won the primary. Goldsmith ultimately lost the general election to Democrat Frank O’Bannon.

The county chairmen aren’t the only supporters Mourdock is trying to rally. During a trip earlier this month to Washington, D.C., he reportedly met with Sen. Jim DeMint (R-S.C.) and former Speaker Newt Gingrich (R-Ga.), as well as a number of conservative organizations, including the Tea Party Express, the National Rifle Association, Americans for Tax Reform, the Club for Growth and the National Republican Trust Political Action Committee.

Several of those groups backed conservative insurgents against establishment favorites during Republican primaries in 2010. The most prominent example was the Tea Party Express and the Club for Growth boosting attorney Joe Miller’s candidacy against Sen. Lisa Murkowski in Alaska. Miller defeated Murkowski in the primary, but she won re-election in a historic write-in campaign.

Already the Tea Party Express has said it wants to unseat Lugar, writing supporters in a fundraising e-mail recently, “We need to build a massive warchest to win more campaigns for constitutional conservatives and defeat people like Dick Lugar.”

When Roll Call asked about the meetings in D.C., Mourdock declined to disclose that he had sat down with the groups. “I’m not going to say who I met with and who I haven’t,” he said.

Hoosiers for Conservative Senate, an umbrella organization for tea party groups in Indiana that want to defeat Lugar, is hoping to choose a candidate that it can rally around. Mourdock said he would welcome their support, but it will take more than a tea party candidate to defeat Lugar.

“What’s more important to me than their endorsement is the fact that when I do a parade in Warsaw, Ind., 20 people show up and they’re willing to wear my T-shirt,” he said, adding that he hopes the 2,500 volunteers who helped with his re-election campaign for state treasurer in 2010 would pitch in again.

Mourdock said he respects Lugar but disagrees with his votes for the two newest Supreme Court justices, Elena Kagan and Sonia Sotomayor, and his efforts helping President Barack Obama pass the Strategic Arms Reduction Treaty. He said he didn’t think many other Republicans, including oft-mentioned state Sen. Mike Delph, would ultimately decide to run for the Senate.

Mourdock, who lives north of Evansville, previously lost bids for Congress in 1990 and 1992. Both times he got 45 percent of the vote against then-Rep. Frank McCloskey (D). Mourdock then served two terms as a Vanderburgh County commissioner from 1994 to 2002. He was elected state treasurer with 52 percent of the vote in 2006 and re-elected with 62 percent of the vote in 2010, getting more than 1 million votes and leading the Republican ticket.