Rep. Joe Sestak (D-PA) will win the Democratic nomination for United States Senate from Pennsylvania, defeating incumbent Senator Arlen Specter (D-PA) who is now legally prohibited from running as an independent.

Update: David Wasserman, Cook Political Report extraordinaire, agrees. And he actually has numbers and professional analysis to back it up!

Update X2: The Associated Press calls it for Sestak, too. So long, Benedict Arlen.