Almost as soon as Senator Specter switched parties in April 2009, becoming a Democrat after almost 29 years as a Republican senator, the knives were out back home. Rep. Joe Sestak (D), a former admiral, was already thinking about running against Specter in the general election, and despite opposition from national Democrats he decided in August to oppose Specter in the party primary.
Specter quickly became a reliable Democratic vote as he tried to shore up his credentials with progressive primary voters, lending support to health-care reform, financial reform, and Sonia Sotomayor’s nomination to the US Supreme Court. But that wasn’t enough to stave off Mr. Sestak, who cast Specter’s party switch as political opportunism and ran away with the May 18 primary, 54 percent to 46 percent.
