Pennsylvania did swing against Toomey despite the fact that he performed roughly on the same level Trump did last year. Plus, there is some population loss in areas such as SW & NE Pennsylvania, so just by acknowledging these facts, no Pennsylvania is not becoming solid Republican any time soon.
South East Pennsylvania (Suburban Philadelphia) was the Republican Stronghold in Pennsylvania until recently. It slowly got more and more Democrat but since around 2010 that trend has stopped. At the same time the rest of the state has gotten a lot more Republican. I volunteered with the RNC. 2016 was the first year Pa was ranked as a Class A1 Swing State. It's the same as Florida and Ohio. It's definitely not a Solid Republican State but it is definitely becoming more Republican.
I personally think that Ohio has for the most part moved into the Republican Column. I think Pennsylvania will take its place.
