Having switched parties, Arlen Specter finds himself in one of the toughest re-election battles of 2010.
Arlen Specter has always been a survivor. The Pennsylvania Senator has endured two bouts of Hodgkin's lymphoma and the chemotherapy that goes with it, a couple of procedures for a recurrent benign brain tumor, and heart-bypass surgery that sent him into cardiac arrest. And in a political career that has spanned 45 years, he has regularly sidestepped doom. Specter's most celebrated swerve came last April, when he switched parties to avoid a Republican primary against a conservative challenger he had barely beaten in 2004. He acknowledged he could never win the GOP nomination for a sixth term after voting for Barack...
