House Budget Chairman Paul D. Ryan endorsed Idaho Rep. Mike Simpson on Tuesday, praising his fellow Republican's work on debt reduction.
“Mike Simpson has been in the trenches fighting to reform runaway spending and has been a critical voice in passing our plan to balance the budget and pay down our debt," the Wisconsin Republican and former vice presidential nominee said in a statement.
Ryan is the latest in a string of endorsements the Simpson campaign is rolling out, including from the Chamber of Commerce and 2012 GOP presidential nominee Mitt Romney . Smith's primary bid is backed by the Club for Growth, which has made Simpson a top target.
The winner of the May 20 primary will be heavily favored in November. The race is rated Safe Republican by Rothenberg Political Report/Roll Call.