I think the reason needs to be - the Democrat party is dying.
The Democrat Party IS dying.
Problem is, a more radical Socialist party is emerging to take its place.
Cue up “Midnight in Moscow” on the turntable...
The Democrat Party is long dead already. The current Party that borrowed the name would have been, 50 years ago, the Communist Party or perhaps the Bolsheviks They have followed the process by which the Social Democrats of Russia, already a Revolutionary party split off the relative “moderates” again and again until they became the Bolsheviks who then took the name Communist Party. The Bolsheviks did it with a large axe. The Democrats have done it with a scalpel.