In a memorable exchange during a Republican primary debate in January 2016, Senator Ted Cruz of Texas needled the upstart candidate Donald Trump, saying he was not a true conservative and adding, “Not a lot of conservatives come out of Manhattan.”

Mr. Trump was ready with a retort. “Conservatives actually do come out of Manhattan,” he replied, “including William F. Buckley.”

It was obvious why Mr. Trump would invoke William F. Buckley Jr. — the author, columnist, magazine editor, TV debater and political candidate who died at 82 in 2008 (and who did work for decades in Manhattan). Mr. Buckley was the leading intellectual architect of the modern conservative movement — indeed, he personified it for more than 50 years.

But by what reasoning could Mr. Trump rightfully claim a connection with him? Outwardly, Mr. Buckley, with his patrician manner, salon wit and gold-plated vocabulary, his passion for Bach and connoisseur’s taste for fine writing, could not have been less like Mr. Trump. And in policy terms, Mr. Trump’s love of tariffs, defense of entitlement programs and isolationist tendencies were at odds with Mr. Buckley’s fondness for the free market, skepticism of big government and support for a muscular foreign policy.

In fact, in the winter of 2016, the editors of National Review, the venerable political journal Mr. Buckley founded in 1955, devoted an entire issue to making the case against Mr. Trump. They invited conservatives “across the spectrum” to argue that he was a “philosophically unmoored political opportunist who would trash the broad conservative ideological consensus within the G.O.P. in favor of a free-floating populism with strongman overtones.”

Since then, the ranks of anti- or “never” Trump conservatives have thinned almost to extinction, in the pages of National Review and elsewhere. Mr. Trump controls the Republican Party top to bottom and commands the loyalty of its policy minds as well as the thriving right-wing media ecosphere. His vision, it seems, has prevailed.