Because now it’s their credibility on the line. They carried the water for Obama and now he’s turning on them. The first law of a Leftist is to get rid of the ones that got you into power because they’re the ones who know where the bodies are buried that’ll sink you.
You make a good point.
Several FReepers have mentioned that the Dems have ceased to consider Republicans as a threat and are beginning their internal purges like Stalin did.