"It could ignite a self-destructive civil war within the GOP just before an election." Please, please, please!
Whether or not Conservative ideology, especially economic ideology, has anything of value to contribute to human society is completely debatable.  But in the hands of the modern Republican Party it is the single most toxic, after-the-fact set of excuses for unfettered greed extant.
The GOP has been building toward Trump ever since Barry Goldwater lost his bid for the Presidency in 1964.  It's not just Trump who's "temperamentally, ideologically and morally unfit" but the entire conservative leadership and constituency.