So, a regression into the EU, rather than being the model for it?

Well, we'd still presumably be working from a common language and a historically shared over-culture; provided the Southwest doesn't become overrun by the Aztlan-cultists, it is pretty much an ideal situation. Plus, it would readily break up the political power the coasts hold over "flyover" country.

Honestly, it's more so luck than it was political maneuvering that the US maintained itself as a single country in a landmass this large with so many countries' fingers in the pie.