Pennsylvania U.S. Sen. Arlen Specter leads Democratic primary challenger, U.S. Rep. Joe Sestak 53 – 29 percent and has pushed ahead of Republican Pat Toomey 49 – 42 percent in a general election matchup, according to a Quinnipiac University poll released today, up from a 44 – 44 percent tie December 18. In a battle of the unknowns, Toomey leads Sestak 39 – 36 percent with 24 percent undecided. President Barack Obama’s job approval rating in Pennsylvania remains below 50 percent, at 49 – 46 percent, the independent Quinnipiac University poll finds.