The Pennsylvania primary was extremely hard fought and, with Senator John Edwards out of contention, it was a major test for Senator Barack Obama. The Pennsylvania campaign included a barrage of negative ads, as well as many changes in position from the Clinton side, depending on where the rallies were held; old-style politics at its worst. The potential weaknesses of both senators Clinton and Obama as candidates in the general election need to be explored. The issue of electability, which is being argued right now by the ultimate deciding constituency—the superdelegates—goes directly to the question that Senator Clinton is trying to raise as substantive: "Do we know everything that we need to know about Senator Obama?" To understand the issue of electability, this chapter reviews the candidates' publicly available information, information that, in both cases, can be distorted to create reasonable doubts.