Obama gave a soaring speech on race as he tried to explain his former pastor's inflammatory sermons, and later defended his own comment about "bitter" small-town Pennsylvanians.
Clinton had to explain her false claims that she dodged sniper fire on a 1996 visit to Bosnia. And the two of them argued over minor differences on free-trade treaties and job losses, health care and energy policy.
Obama holds a wide lead in Philadelphia and a narrower one in its suburban counties, while Western Pennsylvania favors Clinton by as much as 2-1.
Clinton has the advantage among women, older voters, Catholics, union households, and white voters with high school educations making less than $35,000
15 percent of voters who tell pollsters they remain undecided
roughly 325,000 newly registered Democrats in the state
a mixture of first-time voters and those switching affiliation to participate in the closed primary