This is the death rattle of the Republican Party, the final surge of energy before complete extinction. Its true constituency, the hinterland gentry, has reached a state of abject terror and desperation, thanks to demographic change and generational decay, and they have formed themselves into a mindless, violent cult that sees Trump as an actual messiah. This is unsustainable, of course, and it will collapse with startling suddenness. The light at the end of the Trump tunnel is an oncoming train. The only question is just how much damage they can do on the way out. It may take decades to recover our position in the world, with major Constitutional change in the process.
Btw, I think Wendell Zurkowitz is right that Romney foresees this and is positioning himself to pick up the pieces and form a new party.