Hillary Clinton will appear on tonight’s Late Night with David Letterman, which is cool with the WGA because the show’s production company, Worldwide Pants, has struck a side-deal with the union.

But it won’t be cool for for GOP presidential contender Mike Huckabee to appear on this evening’s broadcast of The Tonight Show with Jay Leno. Leno’s show hasn’t signed a separate WGA agreement but will begin airing all-new shows tonight all the same. Huckabee has said “he supports the writers and did not think he would be crossing a picket line, because he believed the writers had made an agreement to allow late-night shows on the air,” says a Time report. WGA picketers have reacted accordingly.