(CNN) - Rick Santorum's taking sides in the free-for-all GOP Senate primary in Iowa.
The former senator from Pennsylvania and 2012 Republican presidential candidate – who's seriously considering another bid for the White House – Wednesday will endorse Sam Clovis. The conservative talk radio host backed Santorum's 2012 presidential campaign, which was fueled by a delayed victory over eventual GOP nominee Mitt Romney in the Iowa caucuses.
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Santorum will make his endorsement through his Patriot Voices PAC.
"I know what is in his heart and Sam is a true, full-spectrum conservative who believes in the greatness of American exceptionalism and the founding principles in our Declaration of Independence and Constitution," said Santorum in an email release obtained by CNN.
"I have watched this race develop and was not going to get involved, but I feel compelled to more publicly voice my support for Sam because so-called conservative groups in Washington, D.C. have tried to anoint a candidate," Santorum added.
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Clovis is one of four major candidates battling for the GOP Senate nomination in the June 3 primary. The winner will face off in November against Democratic Rep. Bruce Braley in the race to succeed five-term Democratic Sen. Tom Harkin, who's retiring at the end of the year.
Santorum becomes the latest out-of-state big name politician to make an endorsement in the contest. State Sen. Joni Ernst has been backed by Sen. Marco Rubio of Florida, former Alaska Gov. Sarah Palin, the 2008 GOP vice presidential nominee, and 2012 GOP presidential nominee Mitt Romney. Matthew Whitaker, the former U.S. Attorney for the southern district of Iowa, has the backing of Texas Gov. Rick Perry, a 2012 Republican presidential candidate who may launch another bid in 2016.
Businessman Mark Jacobs, the former chairman of Reliant Energy, is also one of the four major candidates.
The most recent polling in the race indicates Ernst and Jacobs battling for the top spot, with Whitaker and Clovis trailing.
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Two candidates Santorum recently endorsed won victories in Tuesday's primaries.
Midland University President Ben Sasse, a former Bush administration official, came out on top in the Senate GOP primary in Nebraska. In recent weeks Sasse won the backing of Santorum as well as Palin, and Sens. Ted Cruz of Texas and Mike Lee of Utah, who joined Sasse at a recent rally in Nebraska. Sasse is now the favorite to win November's general election in the race to succeed retiring Republican Sen. MIke Johanns.
And Alex Mooney, who enjoyed Santorum's support, won a wide-open GOP nomination in West Virginia's 2nd Congressional District.