This is essentially what has destroyed the mid-Atlantic up through New England: a heavily populated Marxist Urban Megalopolis that cuts a gash through VA, MD, DE, PA, NJ, NY, CT, RI and MA. All those states are deep blue, except VA, which is on its way to the same. The outlying, less densely populated areas in those states, for the most part, remain far more conservative.
This is true in NJ and DE--I have lived in such areas myself which are conservative, but we were outnumbered by the urban centers.
“...heavily populated Marxist Urban Megalopolis...”
Exactly right analysis. I just read today somewhere that NYC is 40% non English speaking as a first language.
The outlying areas in those states ARE (as you state) far more conservative for the most part, but the university towns and cities (think Ithaca with Cornell, etc.) are making Marxist inroads throughout the outlying areas. The ideology is like a poison spreading, and many of the young people are buying into it.