My theory is that during the Great Depression (instigated and worsened by FDR and his socialist mob), the leftist DemonRATS of the South moved north in search of jobs. They brought their liberals ideas to New England and turned it from the GOP to the 'RAT side forever. The Southerners who remained in Dixie were those of solid Christian and Jewish values, naturally Conservative and pro-America. And, IMHO, that's why the South transformed from DemonRAT to Republican. The so-called "Southern Strategy" has been discredited as a leftist fabrication, thus I attribute the change to regional migration of Southern liberals to the north.
You may be on to something. Certainly plenty of southern blacks moved north, but there were whites migrating too. Here in Chicago, for decades there was a pocket of southern transplants in the Andersonville neighborhood, and you can still go to their local bar, where the Confederate flag is hanging on the wall, and Hank Williams Sr is on the jukebox.
Missouri and Michigan used to be more important than California.
Wow