Sen. Jim DeMint (S.C.) on Wednesday declined to endorse fellow Republican Sen. John McCain (Ariz.) in his GOP primary campaign over conservative former Rep. J.D. Hayworth (Ariz.).

DeMint, who has been active in Republican Senate primaries across the country and funneled hundreds of thousands of dollars to his preferred candidates through his Senate Conservatives Fund political action committee, told Fox News he would not pick sides in the Arizona GOP contest.

“I’m going to stay neutral in Arizona,” DeMint said.

The conservative South Carolina Republican and former House Member has been a thorn in the side of his party’s establishment and, in some instances, the National Republican Senatorial Committee.

DeMint is backing state Assemblyman Chuck DeVore in the California GOP Senate primary, even though DeVore is seen as the Republican with the least likely chance of beating Sen. Barbara Boxer (D-Calif.) in the general election. Meanwhile, DeMint endorsed former state Speaker Marco Rubio over Gov. Charlie Crist in the Florida GOP Senate primary.

In Arizona, Hayworth recently gave up his radio talk show to challenge McCain, the GOP’s 2008 presidential nominee, in the Aug. 24 Republican primary.

Hayworth lost his Phoenix-area House seat in 2006, when he was defeated by now-Rep. Harry Mitchell (D).