(CBS News) During most of his 30 years in the Senate, Arlen Specter was best known as a moderate Republican. He served on the powerful Senate Judiciary Committee, where he's remembered for his opposition to conservative Supreme Court nominee Robert Bork in 1987 . . .
"The concern I have is, where is the predictability in Judge Bork," he said.
. . . and for his aggressive questioning of Anita Hill during the Supreme Court nomination hearing for Clarence Thomas in 1991.
He was a Ranking Member who quickly climbed the political ranks to become Pennsylvania's longest-serving Senator.
"I won the election because of attention to Pennsylvania over 24 years," he said in 2004.
Even before coming to Congress, Arlen Specter had already made a name for himself as Philadelphia 's District Attorney.
He gained national attention in the 1960s when he served on the Warren Commission, which investigated the Kennedy Assassination, and he's credited with the co-authoring the "single bullet" theory.
First elected to the Senate in 1980, Specter won five terms, until he announced he was switching parties in 2009.
"As the Republican Party has moved farther and farther to the right, I have found myself increasingly at odds with the Republican philosophy and more in line with the philosophy of the Democratic Party," he said.
Two years later, he ran for re-election as a Democrat, and lost in the primary.
He put an end to his longstanding political career - and jumpstarting his return to his other loves, the law . . . and comedy. He recently appeared at Caroline's Comedy Club.
"I've been in the Senate for 30 years practicing comedy," he explained earlier this year.
During his time in Congress his biggest battle was cancer. He overcame a brain tumor, non-Hodgkins lymphoma, and was recently diagnosed with a new form of the deadly disease, which he confirmed in a statement
"I'm battling cancer," he said. "It's another battle I intend to win."
Specter died Sunday at age 82.