Sen. Arlen Specter lost his bid for a sixth term, succumbing in the Democratic primary to relative newcomer Joe Sestak, a two-term congressman who successfully campaigned against Specter's recent party switch. Specter's loss represents the biggest rebuke of incumbent lawmakers so far this year. "Philadelphia generally does not vote as strongly as the rest of the state in primaries to begin with," said Joseph McLaughlin, director of the Institute for Public Affairs at Temple. "And coupled with the rain — rain is not good for Arlen Specter," he said.