Pennsylvania is NOT a swing state no matter how many times the media claims it is. It's not a "swing" state if a 27-year old was not alive the last time the Republican Party won it.
PA has exhibited a worrisome trend towards the Republicans in the last 2 elections though. As much as Democrats talk about VA trending left, PA has trended right, at least temporarily. In 2004, Bush won nationally by 2.5 points, and lost PA by 2.5, making it D+5. In 2008 it was D+4, and then it was a pitiful D+1 in 2012 compared to the national average. If Romney had won by a mere 2.5 points nationally like Bush did, then he would have won PA. Republicans losing PA so much is mostly a factor of them being so pathetic and radioactive at the national level, having lost the PV in the last 5/6 elections. It is great to see PA being so solidly in Hillary's corner. She is better fit for the state than Obama.