Veteran GOP Sen. Arlen Specter of Pennsylvania announced Tuesday he will switch political parties and run in the Democratic primary in 2010.
Republican voters had sent him to the Senate five times. But faced with the prospect of a strong challenge from conservative Pat Toomey in the GOP primary and the state trending Democratic, Specter issued a statement that he was going to jump ship.
"I deeply regret that I will be disappointing many friends and supporters," Specter said at a news conference on Tuesday.
"I can understand their disappointment," he continued. "I am also disappointed that so many in the party I have worked for for more than four decades do not want me to be their candidate. It is very painful on both sides."