Republicans who think that "Trumpism" will just go away after Trump loses and that the Republicans will nominate another Bush-type Republican in 2020 are deluding themselves.
I don't think Trumpism is just going to go away (and definitely not by 2020), but at the same time you've got to recognize that it's a minority of the party (disliked by the majority, incidentally), one that will not find it easy to coalesce around one candidate in the absence of Trump, and one which has a massive demographic problem in that it gets support mostly from older voters in high-mortality areas.
I don't know what is meant by "Bush-type" (I don't think a hawkish FP-oriented candidate, like Lindsey Graham, has much of a chance in the modern Republican Party, but none of the serious prospective 2020 candidates really fits that description; Cotton is the closest but he's clearly intending to compete for Trump-successor), but I think a Trumpist would need even better luck than Trump had in 2016 to win in 2020, and that after that unless they manage to actually elect a President the prospects become very grim.
I can only speak for myself, but I'd like to see a Kasich-type Republican who isn't as hawkish as the rest of the Republican party nominated in 2020. Even a populist Republican would be great unless they run a "Whites only" campaign.
That candidate wouldn't be my first choice, but I would definitely still back him in the general. (Referring to your first sentence; "populist Republican" refers to a style of rhetoric/campaigning and I judge candidates by ideology and governing/legislative record, so it could be anything from someone fantastic to someone worse than Trump).
Republicans who think that "Trumpism" will just go away after Trump loses and that the Republicans will nominate another Bush-type Republican in 2020 are deluding themselves.
I don't think Trumpism is just going to go away (and definitely not by 2020), but at the same time you've got to recognize that it's a minority of the party (disliked by the majority, incidentally), one that will not find it easy to coalesce around one candidate in the absence of Trump, and one which has a massive demographic problem in that it gets support mostly from older voters in high-mortality areas.
I don't know what is meant by "Bush-type" (I don't think a hawkish FP-oriented candidate, like Lindsey Graham, has much of a chance in the modern Republican Party, but none of the serious prospective 2020 candidates really fits that description; Cotton is the closest but he's clearly intending to compete for Trump-successor), but I think a Trumpist would need even better luck than Trump had in 2016 to win in 2020, and that after that unless they manage to actually elect a President the prospects become very grim.
This would all be true if he loses by 12, but if he loses by 2, as now looks far more likely, this isn't over. Trump will either anoint someone or run again himself in 2020. Assuming it's Trump, Cruz and an establishment favorite like Rubio or Ryan, that's a perfect recipe for an even 3 way split of the party and 1924 Democrats style chaos at the 2020 GOP convention.
The gist of my post was that this isn't over even if he does lose by 12, but there are serious structural issues a Trump '20 candidacy, or a different future Trumpist candidate, would have to face.
I don't think the 60% of the party that opposed him in 2016 would magically become more favorable to him after he lost to a Democratic candidate with sub-40% approval ratings. In fact, I don't think his own backers would see him particularly positively after such an event. Even if it's narrower than 2%.
The wing that backed him would still be greater than 1/3 of the party in 2016, and a candidate who could unify them would be a force; but someone who could unify the forces against them (something Rubio came much closer to doing in 2016 than people remember) would crush them everywhere except New England and maybe a few inner Deep South states.
I think the fact that the Republican base (i.e. everyone except the super-wealthy donors and the consulting/journalist class who collectively number in the tens of thousands) is more or less okay with voting for Trump should be concerning.
The "true conservative" Evan McMullin candidacy has proven to be a complete joke, and the Libertarian ticket that consists of two Republican governors is apparently taking more votes away from Clinton than it is from Trump.
A significant portion of the Democrats have reservations about voting for Hillary, as recent polls indicate, but Republicans seem to have no qualms about voting for Trump. (His ceiling is inherently lower but his floor has held up much more strongly than hers.)
Bloggers at National Review and RedState may be saying, "This isn't what the Republican Party is!" but they can't outvote the rank-and-file voters. And if the rank-and-file voters don't decide what their party is, then what is the point?
