In competitive primaries around the country, Republicans are attempting to prove they are the most conservative candidate in the race. Look no further than Arizona, where Sen. John McCain -- the party's presidential nominee just two years ago -- is being challenged by J.D. Hayworth for not being a "true" conservative.

The same thing is happening in Florida, where Gov. Charlie Crist appears on the verge of exiting the race altogether because of the popularity of the more conservative Marco Rubio.

It's also true in the open seat race in Indiana, where former Sen. Dan Coats, former Rep. John Hostettler and state Sen. Marlin Stutzman continue to battle for the conservative mantle less than two weeks before the May 4 primary. Coats was recruited by the national party and is widely considered the favorite, but all three have led Rep. Brad Ellsworth (D-Ind.) in general election polling.

With Sen. Evan Bayh (D-Ind.) retiring, the eventual Republican nominee will be favored to win the general election. Before President Obama's 1-point victory in 2008, Indiana had voted Republican in all but three presidential elections dating back to 1928.

It's a culturally conservative state, and in general, more conservative Republicans turn out for midterm GOP primaries. To prove their conservative chops, each has unveiled a major endorsement in the past week. On Friday, Hostettler announced the support of Texas Rep. Ron Paul, who has a nationwide network of supporters.

Sen. Jim DeMint (R-S.C.), who was the first senator to publicly back Rubio, entered the fray on Tuesday by endorsing Stutzman and raising -- as of last night -- $77,000 for him through his Senate Conservatives Fund PAC, which supports only "rock solid conservatives."

"Marlin Stutzman can win this race," DeMint states in a fundraising solicitation. "He is surging in the polls and there is still time to elect a true conservative who will stand up to the establishment in both parties."

The Coats campaign responded by rolling out its own conservative endorsements this week: James Dobson, founder of the conservative group, Focus on the Family, and Rep. Mike Pence (R-Ind.), who previously indicated his support for Coats weeks earlier when the former senator was set to enter the race.

"Dan Coats' integrity and conservative record make him the best candidate for the job," Pence stated in a press release. "Dan is a proven conservative leader who is trusted by Hoosiers."

When asked whether Pence would actively campaign or fundraise for Coats, a Coats spokesman responded simply: "Stay tuned."

Pence himself considered running for the seat, but declined before Bayh's retirement announcement. Bayh's exit, the landscape of the state and subsequent polling moved the seat into vulnerable territory for Democrats. RCP now ranks the race as Lean Republican.