The only hope for nonviolent resolution lies in the hands of the Republican congressional leaders.  If they confront Trump with a clear message, he must either heed  them or end up totally isolated.  The message would have to be:  "You must accept us as full partners.  That means we will sometimes say no and you will have to take it.  We will allow only constitutional action.  We will pass laws intended to carry out an intelligible Republican governing philosophy of XYZ.  You will sign them.  If you are tempted to go over our heads and appeal directly to your already diminished base of support, remember that we hold the whip of impeachment.  Since the Democrats would be on board automatically, it would take only a handful of us to tip it in that direction.  Shape up or ship out."  Conceivably, they could go down in history as the men who saved their country.  

Well, it's a nice fantasy, anyway.  More likely, it will all get settled in the streets of the (overwhelmingly blue) cities.