The Pennsylvania senator Arlen Specter is switching to the Democratic party today. He got lots of heat from Pennsylvania Republicans for voting for the stimulus package-he was one of only three Republicans to do so-and his prospects for reelection as a Republican were pretty bad. Specter's move gives the Democrats 59 seats in the house...just short of the filibuster-breaking 60.This puts a lot of pressure on Minnesota, where Al Franken and Norm Coleman are locked in the longest unresolved Senate contest in history. Coleman keeps asking for recounts, losing them, and challenging the results. If Franken wins, which looks likely (although who knows when), the Democrats would have a filibuster-proof majority.How much that matters depends, of course, on how Specter and others actually vote. He was an iconoclast as a Republican and will probably remain one as a Democrat.You can read Specter's statement in full here. It's pretty short.