Putting it bluntly
Why has [Nikki] Haley come out so strongly in favor of Trump? Why has [Mark] Sanford given up the fight for the nomination? Because both of them accept something that the remaining Never Trump Republicans simply refuse to admit to themselves: The party they once knew and loved, the party that I once admired (while also dissenting from it in numerous areas of policy), is dead and gone, replaced by a party whose voters strongly, overwhelmingly support the presidency of Donald Trump.
Jonah Goldberg, Michael Gerson, and George F. Will could talk the ghost of Ronald Reagan himself into challenging Trump in 2020, and Trump would trounce him.
I checked out of the GOP in January of 2005 for reasons, not surprisingly, independent of Trumpism. I haven’t regretted my decision, but I regret the even worse fate that has befallen my former political home over the last four years.