Traitor.
I think calling George Will a traitor would mean that at one time he had conservative ideals he was now betraying, He didn't. Go back and read his columns from the Reagan years, he talked about Reagan as badly as he talks about Trump, he often called Reagan a reckless cowboy who was going to start WW III and all the other liberal talking points. The only Republicans Will defended were RINO's like John McCain, Mitt Romney and George H.W. Bush.
George Will always played the role of a conservative foil to get columns published in the Washington Post and New York Times. He might occasionally give lip service to some moderately conservative idea, but at the end of the day the editors knew he would never really defend any idea that was truly conservative.