Sen. Arlen Specter defended his decision to switch parties as the consequence of a party that drifted too far to the right and a potential jury pool -- Republican primary voters -- that were predetermined to be hostile to him. 

"I am not prepared to have my 29-year record in the Senate decided by the Pennsylvania Republican Primary electorate," he said. "I am prepared to take on all-comers, all comers in a general election."

Specter said he would not be an "automatic 60th vote" for Democrats. He reiterated his opposition to the Employee Free Choice Act, saying that he would also oppose a filibuster-killing cloture vote. And he said he was still uncomfortable with Office of Legal Counsel nominee Dawn Johnsen.

Specter, 79, is in remission from Hodgkin's disease. Be he said he was ready to "take on new things," and was full of "vim, vigor and vitality."

We want to hear what you think about this article. Submit a letter to the editor or write to letters@theatlantic.com.