Pennsylvania Senator Arlen Specter may have been called an opportunist for switching from the Republican Party to the Democratic Party near the end of his long career in the U.S. Senate. But was his switch a sign of political expediency or the result of a Republican Party that had simply moved too far to the right to have room for a longtime moderate? It’s a question many are pondering. Specter died Sunday at the age of 82 after a battle with non-Hodgkin lymphoma.

Specter, who served in the U.S. Congress for 30 years, switched from the Republican to the Democratic Party in 2009 after it became apparent that he would lose his bid for the Republican nomination. Specter lost the nomination to Democratic Rep. Joe Sestak, who continued to hold Specter in the highest regard. “Here’s a man that was willing to stand up to his party. A vote he knew would harm his career,” Sestak told the Morning Call. “It was an honor to be in the arena with him. Nobody, nobody outworks Arlen Specter, and I work hard. I mean he is the best of the best and I was in there with him. It was an honor.”

Specter was a pro-choice Republican in a political climate in which such politicians were becoming a rare breed. Politico notes,”Specter backed abortion rights and federal funding for stem-cell research, positions sharply at odds with the GOP leadership and party base.” But it was his vote to pass the Affordable Care Act, as well as the stimulus plan, that caused the final schism between Specter and the Republican Party.