There is one major flaw in Mr. Kass's reasoning.  The Democratic party was the party of slavery well over a century ago.  It was the party of Jim Crow over 50 years ago.  Today it is the party that most strongly stands against those racist institutions.  Yet the Nazis, KKK and white nationalists fighting to hold on to their white supremacist "cultural heritage" still espouse the same racist ideology they always have.  The Democratic party has evolved.  The white supremacists have not.