As you note, the GOP knowingly nominated Mr. Trump to be their candidate.  Trump has been a high-profile lout for thirty years.  He's hardly a "surprise package."  I don't blame Party leaders and down-ballot candidates from tossing that "lepers' bell" around his neck and running away as far and fast as possible.  They're now working to save their own political future and the future of the Republican Party.  

Of course they should never have nominated him in first place...duh...we all know that.  However, they did and now the task is to minimize the damage.. 

There are those who will support Trump to the "bitter end" and will condemn those who don't as "turncoats" and "cowards".  Those Trump zealots represent the "new" base of the GOP and I think we'll see a huge battle over Party control in the wake of the Trump disaster.  I think the GOP will conclude that their "walk on the wild side" of hardcore right-wing politics didn't work out real well.  ......Stay tuned for GOP excitement..