NEW YORK — Late last week, Robert De Niro walked onto a Tony Awards rehearsal stage at Radio City Music Hall and, with the military efficiency common to such proceedings, read quickly off a teleprompter.

The “Taxi Driver” star was scheduled to introduce a performance by Bruce Springsteen at the live show. So he recited the short bit of boilerplate about the Boss, then quickly ceded the stage to another presenter. None of the crew of several dozen in the room thought anything of it.

On Sunday night, the actor took the same stage. He stood in the same spot and read the same script — then went wildly and laceratingly off it. Amid roars of approval from many of the 6,000 who had gathered, bowtied and bejeweled, for the annual Broadway rite, the actor spit out, “F— Trump,” using an expletive. Then, in case, anyone missed it, he circled back. “It’s no longer down with Trump,” he said, “but f— Trump.” He shook his fists in the air. The crowd came to its feet and roared louder.

No U.S. viewer watching at home heard De Niro’s remarks — an employee of CBS, which had the telecast on a seven-second delay, bleeped them out. But no viewer needed to. Within minutes, the moment had gotten out on social media.

And just like that, both a Broadway extravaganza and a beloved American actor had become a lighting-rod referendum on Trumpism. (Conservative pundit Laura Ingraham on Twitter: “Another ‘celebutainment’ gift to the GOP & @realDonaldTrump. #MeettheFockers. Stormy Daniels’s lawyer Michael Avenatti tweeted, “I’ve always enjoyed fellow Paisan Robert De Niro’s work.”)

As a cultural industry that has long been informed by, and intent on sending messages about, the dispossessed, Broadway has been at the vanguard of the movement to fend off Trump’s more isolationist policies. But it has sometimes taken different roads in getting there, as much preaching unity in the face of divisiveness as using the tools of division itself.

As it happened, De Niro’s speech evoked another political Broadway moment that quickly went viral. Less than two weeks after Donald Trump and Mike Pence won the 2016 election, one star of the smash historical musical “Hamilton,” aware that Pence was in the audience, addressed him directly, actor Brandon Victor Dixon making a plea for inclusion.

The level of vitriol on Sunday was, at first glance, a sign of how much the discourse has devolved.  “There’s nothing to boo here, ladies and gentlemen, there’s nothing to boo here. We’re all here sharing a story of love. We have a message for you, sir,” was how Dixon addressed Pence in November 2016 — a far cry from De Niro’s obscenity-laced protest cry on Sunday night.

But it’s also worth pointing out that for much of Sunday evening, Broadway actually took a more Dixonian tack itself, cloaking pleas of tolerance in the garb of stage inclusion.

Acting winners Ari’el Stachel and Tony Shalhoub, from the best musical-winning cross-cultural Israeli-Arab story “The Band’s Visit,” spoke about their Middle Eastern parentage and the value of immigrants as they accepted their Tonys. “I want to connect this moment to a moment that occurred nearly a century ago, in 1920, when my father arrived on a boat from Lebanon and first set foot here on Ellis Island. He was then just a boy of 8,” Shalhoub said. “So tonight I celebrate him and all of those whose family journeyed before him and with him and after him.”

Andrew Garfield, landing a Tony for playing the landmark gay character Prior Walter in the revival of the Pulitzer winner “Angels in America,” said, “Let’s just bake a cake for everyone who wants a cake to be baked,” referring to the recent Supreme Court decision in favor of the Colorado baker who cited religious freedom in turning down a request to cater a same-sex wedding.

In fact, the most viral moment at the Tonys — well, until the De Niro speech — occurred when teenage survivors of the school massacre in Parkland, Fla., sang “Seasons of Love,” from “Rent.” “How do you measure a year in a life?/How about love? Let’s celebrate, remember a year/In the life of friends.”

Unlike De Niro, that moment was planned by Tony’s producers. Several students at the school had reached out to thank Tony’s organizers for a benefit that some Broadway veterans had done at the Marjory Stoneman Douglas High School and said they would like to express that gratitude at the Tonys. The producers said they would do them one better and invited them to sing on the show.

The producers even kept the number out of a dress rehearsal Sunday morning so word wouldn’t get out and minimize the impact. When it unfolded Sunday night, the performance landed with a thousand Twitter tears.

The two Tony Awards instances offered a case study in how the nation’s cultural industry has approached Trump — with knives and with hugs. Parkland teenagers went with a call to understanding. De Niro — a creature far more of Hollywood than Broadway, it’s worth noting — chose a call to action.

His moment doubled down on liberal entertainers’ recent penchant for (and continued a right-wing backlash to) profanity about the White House, following Samantha Bee’s remarks about Ivanka Trump two weeks ago. This time there was no quick mea culpa, no explanations of the four-letter word as an exclamation point on a long policy analysis. De Niro’s Trump-aimed expletive was not a comic culmination but the main reason for his speech.

(Sitting somewhere in the middle was a different award-show moment: Meryl Streep’s 2017 Golden Globes speech, in which she tore into Trump’s isolationist policies with De Niro-ian vigor but never mentioned his name, with Shalhoubian subtlety.)

Sunday night was filled with ironies. That Springsteen was taking the stage to sing an ode to the working-class people of his native Freehold, N.J., only highlighted how garbled these messages had gotten — the people De Niro was potentially alienating were being celebrated by the artist he was introducing.

Meanwhile, Laurie Metcalf, co-star of the feminist “Three Tall Women,” may have gotten a Tony boost thanks to, of all things, Roseanne Barr’s racist tweet. Barr’s comments about Valerie Jarrett and the subsequent cancellation of “Roseanne” put Metcalf in the news sympathetically as fans called for a spinoff centered on her progressive Jackie character. That might have helped her bid with liberal Tony Awards voters: just a few weeks ago, Metcalf was thought an almost-certain loser to “Angels in America’s” Denise Gough. On Sunday, she pulled off a startling upset.

It was also an evening rife with confusion. Would De Niro’s moment become a blip or a new normal for liberal entertainers; was this an outlying incident or a signature moment? The effect on De Niro himself also remains to be seen. Moments like this tend to elicit calls for actor boycotts. Then again, few of those calls have come against actors as Teflon as Robert De Niro.

At the parties around the city that followed the ceremony and stretched late into the night, the Trump moment was on many Broadway veterans’ minds. They just couldn’t figure out what to make of it, or whether what he did was a good thing.

“I used to think it was good for people to call Trump out,” Kenneth Lonergan — the liberal playwright behind the best revival of a play nominee “Lobby Hero” and Oscar-winning screenwriter of “Manchester by the Sea” — told The Washington Post at one gathering. “I’m just self-defeatist about it. I guess a lot of people like Robert De Niro,” he said. “But is he really going to change anyone’s mind? It just becomes more fodder for the right.”

Others were embracing the actor’s sharpness, casting aside those who said De Niro went too far or would defeat liberals’ own purpose. “Good. Good that he said that,” Jelani Alladin, who plays Kristoff in Disney’s musical “Frozen,” told The Post at another post-Tonys event.

Alladin is the rare black actor who tackles a role on stage that had been portrayed as white in a movie, and he said it was the same spirit of progressive boldness in which he took De Niro’s comments. “Why are we pretending art isn’t political? Who does that benefit? What good does it do to sit back? This is a new moment, and as artists we need to embrace it.”