I see the Never Trump movement splitting into two strands. John described the first strand here. It’s the view that most of the things Trump has done as president in terms of personnel and policy are desirable but that they are outweighed by the things Trump does that, in Bill Kristol’s words, “degrad[e] our public life.”
So stated, this strand of Never-Trumpism is hard to defend, for the reasons John stated. However, if one adds policy issues where Trump seems to deviate from conservatism as understood by the Never Trumper — e.g. free trade and a decidedly interventionist foreign policy — one can find coherence in the Never Trumper’s position. But not, in my view, to the point that it makes sense for him to wish Hillary Clinton were president.
The second type of Never Trumper finds less to give Trump credit for because she has changed her positions on substantive positions as a result of Trump’s embrace of them. Jennifer Rubin is the reductio ad absurdum of this strand. Max Boot, the Never Trumper who says he’s “learned about” his “white privilege” in 2017, is another example.
This strand of Never-Trumpism is more coherent than the first because there’s less dissonance between the Never Trumper’s policy views and his alienation from Trump. However, it is also less principled because policy views are being driven by matters of personality.
David Frum is a special case, I think. His restless, iconoclastic mind had caused him to rethink his conservatism before Trump arrived on the political scene. Trump may have accelerated the rethinking, but it wasn’t the cause.
David Brooks is a similar case. However, by 2008 he had “rethought” himself into supporting Barack Obama for president over John McCain, a man he admires. I view the Never Trumpers as those who were pretty solidly conservative when Trump landed, but who, to this day, have no use for him in spite of his conservative policies and personnel decisions. David Brooks does not meet the first part of this definition, in my opinion.
Putting Frum and Brooks to one side, I doubt there is any genuine way back to conservatism for those in the second strand of Never-Trumpism movement. Many of them may not want a way back (though I suppose Rubin will remain the Washington Post’s “conservative” blogger).
There may be a way back for those in the first strand, though probably not if they refuse to back President Trump, at least nominally, when he runs in 2020 against Kamala Harris, Elizabeth Warren, or whichever hard-leftist the Democrats nominate (assuming such a race comes to pass).