http://www.fivethirtyeight.com/2009/04/but-now-hes-our-no-good-dirty-rotten.html
One criticism of Arlen Specter I don't quite get, at least coming from liberals, is that his party switch reflects poorly on his character. Glenn Greenwald and Jon Chait, who don't actually agree on all that much, respectively call him "soul-less", and an "unprincipled hack".
Of course this is true, in so far as it goes. Specter has not been shifting to the left gradually over time, as one might expect from someone whose ideology was slowly "maturing". Rather, according to DW-NOMINATE data, he's actually moved slightly to the right in recent years, along with the rest of the Republican Party.
But if you're a Democrat, would you really want Arlen Specter to be anything other than a soulless, unprincipled hack? If Specter were more concerned about self-consistency -- and less about self-preservation -- he'd probably still be a Republican right now. Moreover, Democrats had better hope that Specter is as nakedly power-hungry as possible, because his best move from the standpoint of self-preservation is probably not merely to become a Democrat but to become a reasonably liberal one, along the lines of Bob Casey Jr.
Interesting...