This time, the tea party freshman has helped the lower-profile Madison Project, a political action committee working to defeat McConnell and Sens. Pat Roberts of Kansas and Thad Cochran of Mississippi — and prop up other primary challengers in 2014 midterm races. In the mailer, Cruz asks donors to “pull out all the stops” to elect “solid, principled, conservative fighters” who will “not answer to the party bosses in Washington, D.C.”

While Cruz doesn’t single out any candidate by name, he praised the group for recruiting “viable conservative candidates” and pushing them through “every single step of the pathway to victory” in 2014.

“Our nation desperately needs more strong conservative fighters in the Senate … not more moderate, career politicians who will sacrifice principle and compromise with Democrats at every turn,” Cruz writes in the fundraising solicitation. “In short, it’s time to elect some conservatives who won’t run from a fight!”

The letter — which is undated but was provided to POLITICO from a person who received it in the last month — comes after Cruz told GOP senators last October he would not raise money for the Senate Conservatives Fund, another conservative group launching full-throated attacks against GOP senators in their 2014 primary campaigns.