Former Bush speechwriter Marc Thiessen has an unintentionally funny item entitled, "A Conservative Insurgency, Not A Purge." He writes:

In the Washington Post today, I explain that far from a “purge movement” aimed at accumulating “RINO pelts,” DeMint is leading a carefully targeted effort to elect a handful of real conservatives who will help him fight for fiscal discipline and conservative values in the Senate.

What, you may ask, is the difference between a purge and an insurgency designed to elect real believers in your side's ideology? Obviously, when your own party is doing it, it's the latter. When the other party does it, it's a purge. Joe Lieberman was purged. Arlen Specter was simply the loser of a targeted effort to elect a handful of real conservatives who will help fight for fiscal discipline and conservative values in the Senate.