The idea that by backing Donald Trump “Reaganite conservatives” would be “sleepwalking toward a kind of ideological suicide” is being advanced by Ross Douthat. He does this in his latest column in the Times, a newspaper that has sought to kill off Reaganism at every turn. No one would blame the heroic Mr. Douthat for the policies of the Times. But as for the sudden solicitude in respect of Reaganism from the Times, well, let us savor the ironies.

Mr. Douthat allows that successful leaders often transform their parties. He cites William Jennings Bryan and Woodrow Wilson, who, he proposes, “turned a conservative Democratic Party progressive.” Then again, too, that depends on what one means by progressive. In 1896, William Jennings Bryan sought to gain a mandate for inflation by running a campaign so anti-Semitic that David Duke would have blushed.

Yet a century later, the Democrats have yet to demand that Bryan disavow his own David Dukes. Go figure. As for Woodrow Wilson, he may have been progressive on some matters, but once he got into the White House, he segregated the army and civil service, setting back the cause of equal rights for decades. It was the GOP, heirs of Republican A. Lincoln, who finally started passing civil rights legislation.

Mr. Douthat reckons that it was Eisenhower who “all but extinguished G.O.P. isolationism.” The Timesman doesn’t deconstruct the Sinai crisis, in which Ike refused to intervene to help Israel, England, and France. Nor, for that matter, does he deal with Hungary in 1956. Nor with Wendell Wilkie, maybe in deference to the Times, which in 1940 endorsed the Hoosier over FDR in terms that that are, to a startling degree, being echoed today.

The nation, the Times said in endorsing Wilkie, needed a “gigantic industrial force behind its army and navy” and therefore a man who “understands business,” has “the confidence of business,” and who “has himself been a part of business.” Could Mr. Douthat have missed the Times’ own Trumpist tradition? The columnist suggests it was Reagan “himself” who “set liberal Republicanism on the path to extinction.”

Mr. Douthat goes on to say that in a “fully-Trumpized GOP, Reagan’s ideological coalition would crack up, with hawks drifting toward the Democrats, supply-siders fading into crankery, religious conservatives entering semi-permanent exile.” Never mind that it was the seer R. Emmett Tyrrell, Jr., who brought in that scoop (in 1992 in “The Conservative Crack-up”). Above all, Mr. Douthat writes, it is “Trump’s authoritarianism” that makes him “unfit for the presidency.”

The columnist is speaking of not only The Donald’s “stated admiration for Putin” and the Communist Chinese but “his promise to use the power of the presidency against private enterprises” as well as Mr. Trump’s “casual threats” against “party donors, military officers, the press, the speaker of the House, and more.” By those tests Mr. Trump could, if he loses, get himself hired as editorial writer at the Times.

Mr. Douthat suggests that Mr. Obama’s power grabs “are part of a bipartisan pattern of Caesarism, one that will likely continue apace under Hillary Clinton.” Well, et tu, Douthat? The distinction he sees is that “far more than Obama or Hillary or George W. Bush,” The Donald “is actively campaigning as a Caesarist,” making a selling point of his contempt for political niceties and “constitutional norms.”

That bit about constitutional norms is touching, coming from the Times. When the Republicans opened the 112thHouse by reading the Constitution from the floor, the Times issued an editorial calling it a “ghastly waste of time.” Mr. Douthat concludes his suicide watch by suggesting that “to Trumpism’s appeal, to Trump’s constituents, conservatives should listen and answer ‘yes,’ or ‘maybe,’ or ‘not that, but how about…’” But “to Trump himself, there is no patriotic answer except ‘no.’” Better, in other words, to fall on one’s sword.