Former Pennsylvania senator Arlen Specter dead at 82

Former U.S. senator Arlen Specter, who represented Pennsylvania for 30 years as a moderate Republican-turned-Democrat, has died, the Associated Press reports.

Specter, 82, had health issues for years, undergoing two brain surgeries, two rounds of chemotherapy and heart surgery before re-entering the hospital in August for what was described as "a serious form of cancer."

Specter had been teaching at the University of Pennsylvania law school after his re-election defeat in the 2010 Democratic primary to Rep. Joe Sestak, shortly after abandoning the Republican Party because of what he called "irreconcilable differences."

Specter had been critical of GOP efforts to impeach President Bill Clinton and the secret wiretapping of American citizens under President George W. Bush.

Upon his departure from the Senate, Specter lamented the dwindling number of centrists. "Moderates and some conservatives have fallen like flies at the hands of the extremists in both parties," he said.