The civil war between Trump supporters and other Republicans was inevitable, if not before the election than afterwards.
Last fall I bet that Trump would get the nomination because it was clear that a large chunk of the Republican base was angry NOT at the corporate elite, NOT at trade, but mostly at the Republican leadership itself. Some degree of economic resentments played a role there, but it was mostly anger that Obama kept winning elections, Obamacare and other Obama initiatives were not repealed, and there was a clear sense among that base that the GOP leadership had willingly betrayed them.
That hard Trump base may dislike Clinton but they HATE Ryan and the GOP-- and only the band-aid of the pre- and post-Convention hailing of Trump as GOP leader was holding that anger in check. With all the GOP leaders now denouncing Trump, that anger is boiling out again and the civil war within the GOP is just going to keep spiraling out of control. I am really hoping that there is a core of 5-10% of the population in that Trump base that will look to punish the down ballot GOP for betraying Trump, which could be the wave -- or rather riptide -- that yanks the Congressional majority away from the Republicans. A large number of Trump supporters may vote for him at the top of the ticket and deliberately skip voting for GOP Senate and House candidates perceived as betraying Trump. That undervote will be the riptide that could doom Republicans.
Trump is going to leave the campaign with his brand, reputation and probably most of his business deals in tatters -- but with a mailing list of millions of white misogynist nationalists worshiping him and looking for him to lead them in a crusade. Riding the circuit of his crazed followers will be a place where he basks in the adulation he obviously craves -- and will likely be the only venues available for that -- so it seems unlikely for him to abandon his followers. A new television or other media setup with Roger Ailes and others seems likely to further this fight.
At the same time, the corporate wing of the party will have to figure out how to assemble a majority coalition without the Trumpkins, when the policies they promote have nowhere near majority support anywhere and always depended on racial dog whistling to corral votes into the party. If they fully reject the Trumpkins, there is no majority in sight but if they embrace them, they alienate swing voters and doom the party among the rising non-white majority.
So the last twenty-four hours is not a break in the fever but just the opening to an illness that will wrack the GOP for years to come.
Ideally, progressives can take advantage of the opportunity to strengthen support for an alternative vision among its own base, while doing the hard slow outreach to confused GOPers not completely bought into the Trumpkin gospel or wedded to the corporate vision and maybe willing to consider to allegiances having seen where their support for the GOP had gotten them.
Nothing will happen overnight and even regaining Congress this year is still a bit of a longshot, but it's all doable recognizing that there will be real openings to broaden the progressive coalition in coming years.