Major events in the timeline of former Sen. Arlen Specter's career in politics:
— 1959: Hired as an assistant district attorney in Philadelphia.
— 1964: Serves on the Warren Commission, which concludes that a lone assassin killed President John F. Kennedy.
— 1965: Runs successfully on Republican ticket for Philadelphia district attorney, even though he was a Democrat.
— 1967: Loses election for Philadelphia mayor.
— 1969: Elected to second term as district attorney.
— 1973: Loses bid for third term as district attorney.
— 1976: Loses GOP Senate primary.
— 1978: Loses GOP gubernatorial primary.
— 1980: Wins Pennsylvania's open U.S. Senate seat and joins new Republican majority in the chamber.
— 1986: Elected to second term in Senate.
— 1987: Helps defeat President Ronald Reagan's Supreme Court nomination of Robert H. Bork.
— 1991: Aggressively questions Anita Hill during Clarence Thomas' Supreme Court nomination hearing.
— 1992: Elected to third term in Senate.
— 1995: Announces candidacy for president. Suspends campaign later that year amid fundraising difficulties.
— 1998: Elected to fourth term in Senate.
— 2004: Ekes out win in Senate GOP primary, beating U.S. Rep. Pat Toomey by 17,146 votes, or 1.6 percentage points. Wins a fifth term in November.
— 2005: Begins two-year term as chairman of Senate Judiciary Committee.
— February 2009: Votes for Democrats' economic stimulus package, inflaming GOP sentiment against him.
— April 15, 2009: Toomey announces he will mount another challenge to Specter in 2010 Senate GOP primary.
— April 28, 2009: Specter announces he is changing party registration from Republican to Democrat.
— August 4, 2009: Democratic U.S. Rep. Joe Sestak announces his Senate candidacy.
— May 18, 2010: Sestak defeats Specter in Democratic Party primary.
— Dec. 22, 2010: Specter takes last vote in Senate.
— Jan. 3, 2011: Senate term ends.
— Oct. 19, 2011: In speech, Specter blames the tea party for removing GOP moderates, says Washington gridlock has become "like a war."
—Aug. 28, 2012: Confirms that he is battling cancer again, calls it "another battle I intend to win."
—Oct. 14, 2012: Son confirms Specter's death at his Philadelphia home of complications of non-Hodgkin lymphoma.
Copyright 2012 The Associated Press.