Ezra Klein thinks that the reason Joe Lieberman is an unprincipled opportunist is not because he was always an unprincipled opportunist and Democrats in Connecticut wanted to replace him. No, it’s because those foolish liberals made him go bad:

Look at the Senate right now: If Democrats have 60 votes, it’s because conservative activists kept running primary challengers against Arlen Specter. If they fall short, it’s likely to be because liberal activists ran a primary challenge against Joe Lieberman.

I guess my friends and I who spent our weekends trying to help Connecticut elect a genuinely decent human being for Senator should apologize to America for turning Joe Lieberman into an unprincipled skunk. From now on, we really need to support the incumbent protection racket.

And I really need to talk to that Hamsher woman.

Update: Ezra Klein replies, clarifies what he meant.