What I think is going to happen is the the R's will split and form two new parties. The Bat-[Bleeeeep!] crazy white supremecists will be one and the other will be the more or less mainstream Republicans.

At the same time, the Democrats will split with the left Progressive Bernie wing going left and the rest going right. They will meet with the R's in the middle and form a marriage of convenience and power.

The difficult balancing act is that there is fairly large group that is fiscally rather conservative (at least balance the damn budget) but socially liberal. Neither current party, or their splinter groups, accomplish this.