Washington --

Arlen Specter, the irascible senator from Pennsylvania who was at the center of many of the Senate's most divisive legal battles - from the Supreme Court nominations of Robert Bork and Clarence Thomas to the impeachment of President Bill Clinton - only to lose his seat in 2010 after quitting the Republican Party to become a Democrat, died Sunday at his home in Philadelphia.

The cause was complications from non-Hodgkin's lymphoma, said his son Shanin. He was 82.

Hard-bitten and tenacious yet ever the centrist, Sen. Specter was a part of American public life for more than four decades. As an ambitious young lawyer for the Warren Commission, he took credit for originating the theory that a single bullet, fired by a lone gunman, had killed President John Kennedy.

Sharp legal mind


Yet he may be remembered best for his quixotic party switch in 2009 and the subsequent campaign that cost him the Senate seat he had held for almost 30 years. After 44 years as a Republican, Sen. Specter, who began his career as a Democrat, changed sides because he feared a challenge from the right. He wound up losing in a Democratic primary and the seat stayed in Republican hands.

One of the few remaining Republican moderates on Capitol Hill at a time when the party had turned sharply to the right, Sen. Specter confounded fellow Republicans at every turn. He unabashedly supported Roe vs. Wade, the Supreme Court decision that made abortion legal, and championed biomedical and embryonic stem cell research long before he received his cancer diagnosis.

He enjoyed a good martini and a fast game of squash, and was famous for parsing his words to wiggle out of tight spots. During Clinton's impeachment on charges of perjury and obstruction, Sen. Specter, objecting to what he called a "sham trial" without witnesses, signaled he would vote to acquit.

But a simple "not guilty" vote would have put him directly at odds with Republicans; instead, citing Scottish law, Sen. Specter voted "not proven," adding, "therefore not guilty."

Judiciary panel

He relished his work on the Judiciary Committee. In 1987, he enraged conservatives by derailing Bork's nomination to the Supreme Court and then delighted them four years later by backing Thomas. The Thomas confirmation nearly cost him his Senate seat; even now, millions of American women remain furious with him for his aggressive questioning of the law professor Anita Hill, who had accused Thomas of sexual harassment.

Arlen Specter was born on Feb. 12, 1930, in Wichita, Kan., the fourth and youngest child of Harry and Lillian Specter. Harry Specter, a Jewish emigre from Ukraine, moved his family back and forth between the East Coast and the Midwest seeking work before settling in Kansas as a peddler.

The Specters later moved to Philadelphia - "so my sister could meet and marry a nice Jewish boy," Sen. Specter explained - where he enrolled in the University of Pennsylvania. He graduated Phi Beta Kappa in 1951, served in the Air Force, then obtained a law degree from Yale.