NEW YORK >> About an hour and a half into his Broadway performance on Aug. 15, Michael Moore paused his rumpled, moralistic ire to offer the audience an Oprah-style surprise. Two double-decker buses were waiting outside, he said, to whisk theatergoers to Fifth Avenue in a ready-made protest delivered straight to the doorstep of President Donald Trump, the chief target of Moore’s solo show.

There were so many cheers from the audience — who hissed at each mention of the president the way theatergoers once might have booed a vaudeville villain — that Moore checked himself.

“We might need four buses,” he said.

Like any Broadway spectacle, the excursion was a splice of authentic emotion and fabrication. It seemed equal part an earnest bid to get people off the sidelines and into a picket line and equal part showbiz hoopla aimed at bolstering a show that opened last week to mixed reviews and that has not yet caught fire with ticket buyers.

The buses (and the electric votive candles on each seat) were paid for by Moore’s show, “The Terms of My Surrender.” The production also furnished protest signs, a mix of serious messages like “resist” and comedic jabs at the president. “We shall overcomb” one read, beside a Trump-like silhouette.

The signs were handed out to audience members after they signed a waiver and climbed aboard. And though the field trip called to mind a similar expedition by Andy Kaufman, who took his audience from Carnegie Hall one night in 1979 on charter buses for a snack of milk and cookies, it lacked its originality. The nuance of Moore’s early projects like “Roger & Me” seemed to have given way, both on the bus as well as on the stage, to fire-breathing liberalism that speaks mostly to fellow progressives.

Seated in the open air of the buses’ upper decks as they whizzed up the Avenue of the Americas toward Trump Tower, what had minutes before been a Broadway audience buying overpriced snacks and drinking wine in plastic sippy cups swiftly evolved into a fired-up rally.

“I’ve only done what he said we shouldn’t do, which is watch ‘Rachel Maddow’ and sign online petitions,” said Alan Denzer, 66, a retired stockbroker from Bronxville, New York, referring to Moore’s excoriation of armchair resistance that permeates the show, as he sat on the bus. It was Denzer’s first time protesting since the Vietnam War, he said. “He makes you feel guilty a little bit for sitting on your duff,” he said. Today he realized: “I could be more useful.”

The protest came at a politically charged moment, hours after Trump made comments at a news conference blaming both sides, rather than neo-Nazis and white supremacists, for the deadly violence Saturday in Charlottesville, Virginia. The president’s words were addressed in Moore’s show, where he appeared almost pained at the retelling. Many of those who followed Moore to Trump Tower said that if Moore’s buses had not taken them to the streets, Trump’s words that afternoon would have led them to anyway.

As the buses trundled uptown toward Trump’s penthouse, sparks of political passion emerged. Pedestrians on the street joined in chants over a megaphone by actor Mark Ruffalo from atop the lead bus. He had been a special guest on Moore’s stage that night. Even a police officer danced beside the buses, giving two thumbs-up, before a colleague gestured for her to stop.

In his Red Line Tours uniform, Ronald Haynie, 48, a professional New York City guide from the Bronx who had been hired along with the bus for the evening, punched his fist in the air in a joyful Black Power salute. “1968 this!” he said referring to the famed protest gesture at the Mexico City Summer Olympics that year.

At 58th Street and the Avenue of the Americas, the police slid back steel barricades blocking off the street, which were an extra security measure while Trump was in town, and let the buses head east. They drew to a stop by Bergdorf Goodman, where Moore and Ruffalo hung over the front of the bus shouting encouragement at the theatergoers-turned-protesters headed toward Trump Tower at 725 Fifth Avenue. Some paused in their march to ask actress Olivia Wilde, who had joined in the procession, for her autograph.

“This is a way better-looking group than most protesters,” Jason Trentylon, a street promoter who was not part of the bused-in group, said to a friend.

The protest itself was brief. Behind a police cordon just north of Tiffany’s at 57th Street, the protesters chanted and took pictures of one another for about 45 minutes before the group fractured. At one point Ruffalo attempted to lead the crowd to another street corner where he said counterprotesters were assembled, but confronted with security blockades, most went home.

On Fifth Avenue at 58th Street, as the evening wrapped up, Moore stood beside Pulitzer Fountain past 10 p.m., signing autographs, surrounded by news camera crews. How would he respond to any criticism, or critiques of his audience-participation-protest as a stunt?

“Who would say something like that?” he said sharply, before turning and walking away. He climbed into a waiting SUV and left.