Arlen Specter, Pennsylvania's longest-serving U.S. senator, died in his Philadelphia home this morning at the age of 82. His family said his death was due to complications from non-Hodgkins Lymphoma.

Specter started his political career as a Democrat, then spent 44 years as a Republican before returning to the Democratic party in 2009, losing to Joe Sestak in the primary. Specter said in his concession speech that throughout his career he stood up to members of his own party "when that party doesn't get it right for us."

Specter was all but thrown out of the Republican party after casting a vote for the Obama administration's stimulus package in early 2009, and his quest for a sixth term as a Republican in the Senate was stymied by a more conservative opponent. Notably, Specter served as the assistant counsel to the Warren Commission, pointedly questioned Anita Hill, and sought to investigate the abuses at Guantanamo Bay. “The irony is that the very nature of his moderate politics leaves him without a home,” a political scientist noted before Specter's last failed Senate bid. “He’s at a time in his career when he should be being embraced by his party as an elder statesman, but instead he’s being pushed aside. This gives his story an element of tragedy.”