Excuse me, but the Republican party did not disappear over the last 50 years.  They ran against Democrats in all those races.    You blame the Republican failure to connect to urban black neighborhoods on the Democrats?   

Republicans lost, they lost miserably, they offered no policy, no example of how they could fix urban blight.  The only person I  heard address urban poverty in a meaningful was Sen. Jack Kemp and he never got a serious look by the party insiders.

I'm past sick of listening to the blame game.  We have One US Congress, One Executive Branch, One Supreme Court.     Like it or not The Parties are interwoven.  They are failing the nation because of their inability to overcome their self interest.