Politically it is the Midwest
This point is made all the time and I do not understand it. It is only "politically" in the midwest if "Midwest" is synonymous with "swing state," which is just not the case. After all, Illinois, Indiana, and the Dakotas are all in the midwest as well. Also, I'm not convinced that you're right that PA is more similar to MI than NJ or NY or whatever. Even if you want to argue that Pittsburgh is midwestern (which I would disagree with tbh), Allegheny County shifted left from 2012 to 2016! The largest shifts in PA were in NEPA, which is very much not midwestern; the rest of the state experienced shifts more comparable to upstate NY than Michigan or anything honestly, which, again, not midwestern.