“If Trump wins it means the electorate has turned its back on Goldwater-Reagan Conservatism.”
The Republican establishment hated and tried to destroy both Reagan and Goldwater.
I remember how strongly Reagan was hated. Only after Reagan won did the Republican establishment pretend to like Reagan.
"Pretend" is exactly right. The "eastern establishment", "Rockefeller Republicans" have been in charge for at least 65 years, and they DETEST nationalistic tendencies.