PHILADELPHIA - OCTOBER 21: Senator Barack Obama (C) (D-Il) is greeted by Pennsylvania Governor Ed Rendell (L) and Philadelphia City Councilman Bob Brady (R) before speaking during a Democratic Unity Rally at Temple University's McGonigle Hall October 21, 2006 in Philadelphia, Pennsylvania. Senator Barack Obama (D-Il) joined Democratic Pennsylvania Governor Ed Rendell, and Democratic Senate candidate Bob Casey and other Philadelphia regional Democrats at the rally. Rendell faces Republican challenger and former Pittsburgh Steeler Lynn Swann in the gubernatorial election. Casey faces incumbent Republican Senator Rick Santorum.