Rep. Mike Simpson (R-Idaho) (AP Photo/John Miller, File)
Rep. Mike Simpson (R-Idaho) (AP Photo/John Miller, File)

Mitt Romney is getting into the endorsements game, backing Rep. Mike Simpson (R-Idaho) over a primary challenger with the backing of the conservative Club for Growth.

Simpson's campaign announced the backing of Romney on Monday. Romney also sent a fundraising e-mail on Simpson's behalf alluding to groups like the Club targeting the incumbent.

"Congressman Mike Simpson is a proven conservative and 'Idaho tough,'" Romney writes. "But some groups from outside Idaho have decided to attack Mike and distort his conservative record. He needs our help to fight back and set the record straight."

Romney faces attorney Bryan Smith, whom the Club for Growth made its first endorsee of the 2014 election cycle in September.

Simpson is a strong ally of House Speaker John Boehner (R-Ohio) and has a somewhat moderate record. The Club has targeted his district, which went 64 percent for Romney in last year's presidential election, arguing that it should be represented by a more conservative voice.

Romney's backing might not be terribly helpful for most members facing tea party challengers, given his moderate record as Massachusetts governor. But Idaho has a large Mormon population -- Simpson and Romney are both Mormon -- and Romney easily won its GOP caucuses with 62 percent of the vote in March 2012.

Idaho was Romney's second-best state, behind his home state of Massachusetts, until Romney effectively wrapped up the GOP nomination.