His obnoxious use of ethnicity only exposed the fact that Republicans had been using bigotry against minorities and gays to whip up voters for decades. The G.O.P. would love to drop Trump now because it prefers a candidate in the party’s more subtle racist traditions. (Or even a candidate savvy enough to heap disdain on the 47 percent of government freeloaders at a ritzy fund-raiser without having a bartender tape it and leak it.)

The neocons calling Trump a fascist would certainly prefer a more militaristic candidate. Trump realized the Iraq war was misbegotten long before much of the media cognoscenti in New York, and he was willing to hold W. accountable for being asleep at the switch before 9/11 and using a bait-and-switch on Iraq. Even though he ranted about the press, he was also far more available to the media than the cloaked Hillary Clinton, who has yet to give a news conference this year. But he undermines his accessibility when he incites nastiness against reporters at his rallies and revokes The Washington Post’s credentials for a headline he doesn’t like.

Before his campaign became infused with racial grievance, victimhood and violence, Trump told me, “I have fun with life and I understand life and I want to make life better for people.” If he had those better angels, he didn’t listen to them. Seduced by the roar of the angry crowd, Trump kept dishing out racially offensive comments about “my African-American,” a black man he spotted at a California rally; the “Mexican” judge on the Trump University case; and the “Afghan” who committed the atrocities in Orlando. Mitt Romney is right that Trump’s rhetoric causes “trickle-down racism” and misogyny. The Washington Post had a front-page story on Friday about the vulgarities freely directed at Hillary Clinton by men and women at Trump rallies.

Trump told me he could act like the toniest member of high society when he wanted, and he would as soon as he dispatched his G.O.P. rivals. He said his narcissism would not hinder him as he morphed into a leader. But he can’t stop lashing out and doesn’t get why that turns people against him. Everything is filtered through his ego. He reacted to Orlando not as a tragedy so much as a chance to brag about “the congrats” he got for “being right on radical Islamic terrorism.”

The presumptive but now tenuous nominee seemed bereft at a Dallas rally on Thursday night when he could no longer brag about his polls, which are shattering records for negativity. Finally, on Friday, Trump couldn’t stop himself from tweeting out a poll, even though it was one that showed him behind Hillary.