Former state House Speaker T.W. Shannon, one of a handful of Republicans running in Oklahoma’s open-seat Senate race, received the endorsement of the Senate Conservatives Fund Thursday, a group that spends heavily to boost tea-party-aligned candidates into office.  

“T.W. Shannon is a constitutional conservative who will fight to stop the massive spending and debt that are bankrupting our country,” SCF Executive Director Matt Hoskins said in a news release. “We’re supporting T.W. Shannon because he’s a principled conservative, he has strong grassroots support in Oklahoma, and he can win if Americans come together to support his campaign.”  

Shannon will face off with GOP Rep. James Lankford and handful of other Oklahoma Republicans in a special-election primary on June 24. The seat is open because GOP Sen. Tom Coburn will resign at the end of the 113th Congress.  

Conservative groups had initially sought to recruit Rep. Jim Bridenstine, R-Okla., to face off against Lankford in the contest. However when Bridenstine declined to run , it was unclear whether groups such as the SCF and Club for Growth would play in the Sooner State Senate contest .  

The Republican who wins the primary will likely be the next senator from Oklahoma, as GOP presidential nominee Mitt Romney carried the state with 67 percent in 2012. If no candidate garners at least 50 percent of the vote in the June 24 primary, the top two contenders head to a runoff on Aug. 26.  

Oklahoma’s Senate race is rated a Safe Republican contest by Rothenberg Political Report/Roll Call.