Idaho Rep. Mike Simpson out-raised his tea-party-bolstered Republican primary opponent in the final fundraising period of the contest.  

According to pre-primary reports filed Thursday with the Federal Election Commission, Simpson raised $193,000 from April 1 to April 30 and ended the month with $566,000 in cash on hand. Attorney Bryan Smith, who is backed by well-financed outside groups like the Club for Growth, raised $104,000 in April and had $231,000 in cash on hand.  

Simpson and Smith will face off in a May 20 primary in Idaho’s 2nd District. More than $1 million from outside groups has been spent on the race in support of both candidates.  

Business-oriented conservative groups such as the Chamber of Commerce and Defending Main Street PAC, the group run by former Rep. Steven C. LaTourette, R-Ohio, have spent hundreds of thousands to help Simpson survive. The Club for Growth has been on the air attacking Simpson and supporting Smith .  

Should he lose, Simpson would be the first incumbent defeated in 2014.  

Rep. Walter Jones, R-N.C., survived $1 million in outside group spending to defeat a primary challenger on Tuesday . Speaker John A. Boehner and Rep. David Joyce, R-Ohio, also survived primary challenges this week.  

Idaho’s 2nd District is rated Safe Republican by Rothenberg Political Report/Roll Call.