Bush commits a flip-flop!

Yeah, I know, for those of you who pay attention this isn't a surprising revelation. I've just been reading Josh Marshall's comments on last night's Presidential debate. He points out, correctly I think, that the new Rovian strategy for the Bush-Cheney campaign is "liberal, liberal, liberal."

Now I'm confused. If Senator Kerry is the most consistently liberal voter in the Senate, that makes him, uh, consistent. Then how can he be a flip-flopper?

I don't understand. Perhaps Karl Rove can call and explain it to me?