Palin endorsed 64 candidates in 2010 but had been nearly invisible on the campaign trail until last week, when she endorsed Indiana state Treasurer Richard Mourdock (R) shortly before he beat Sen. Dick Lugar (R-Ind.) in a GOP primary.

Cruz is a Tea Party favorite who is currently trying to catch up to Texas Lt. Gov. David Dewhurst (R) in the polls. Dewhurst has millions to spend on the race and can give his campaign even more thanks to his considerable wealth. Former Dallas Mayor Tom Leppert (R) is also spending millions of dollars of his own money on the race.

But polls show the contest tightening some — and a number of conservative organizations are ready to jump in for Cruz in a big way. The fiscally conservative Club for Growth promised earlier this week to spend $1 million on his behalf heading into the late May primary. If no one wins 50 percent of the vote, a runoff will be held in late June.