Mitt Romney's taken the lead in PPP's newest poll of Rick Santorum's home state of Pennsylvania. Romney has 42% to 37% for Santorum with Ron Paul at 9% and Newt Gingrich at 6%. The numbers represent a dramatic turnaround from when PPP polled the state a month ago. Romney's gained 17 points, going from 25% to 42%. Meanwhile Santorum's dropped 6 points from 43% to 37%, for an overall swing of 23 points in the last four weeks.