According to Rasmussen, "Among voters who favor the congressional health care
plan, Specter leads 55% to 26%. However, among those who oppose the plan, Sestak
leads 61% to 25%."
Presumably, both candidates support the plan. But Arlen Specter is an unctuous creature of Washington while Joe Sestak has only been there for three years--and he used to be an admiral before that. Seems to me that this is a pretty clear insider vs. outsider dynamic, and the public might well be in a "throw the bums out" mode unless Specter and the administration get some concrete wins under their belts.