I really think people are overestimating the chances that GOP primary voters are going to keep nominating Trump-like candidates. It's very possible that the party goes back to nominating more "normal" candidates in 2020. In which case, this effort to split off and form a non-Trump conservative party would be rather pointless.
This. These same folks nominated Romney. The GOP primary electorate has barely changed since 2012, and the main way it did was a bunch of people who didn't normally vote showing up to vote SPECIFICALLY FOR TRUMP.I don't know if I agree that that was the main reason. Much of it I'd credit to 1) the fact that Trump got more media attention than all his rivals combined, and 2) the peculiarities of how Trump's opponents divided the vote. Trump was winning with ~1/3rd of the vote in the early primaries, but if he'd faced a different set of opponents, then someone else might have gotten many of those plurality victories rather than him, and used it to build up the support needed to win the nomination over him.
It's not clear to me that a future "Trumpist" candidate will be as adept at generating media attention, or that they won't face a more formidable field of opponents. Of course, it's also not clear to me that there will even be a Trumpist candidate in 2020. It's not like other Republicans are falling all over themselves to run on Trumpist platforms, in those issue areas where Trump diverges from previously established party orthodoxy. Now, some will try to coopt some of his message, perhaps in areas like trade. But that won't necessarily be enough of a heresy from party orthodoxy that it'll scare off #NeverTrump Republicans in the way that Trump himself scared them off.
