Brutus is a commanding figure in the Public Theater’s Free Shakespeare in the Park production of “Julius Caesar.” The wily Mark Antony also looms large. But the most fearsome character in the show isn’t standing on stage — not even in the person of a Donald Trump-like Caesar — but instead storming the bleachers and shouting in the aisles. It’s the mindless Roman mob, or, as director Oskar Eustis’s politically slanted production slyly insinuates, it’s the ecstatic mobs at a Trump rally. Although the show whipped up controversy when funders pulled out over right-wing objections, the furor isn’t warranted: Anyone who reads the plays knows Shakespeare’s main message is that no matter how much you want to get rid of your current political leader, don’t kill him.

In most Shakespeare productions in park, mob scenes have to be taken on faith, with the same handful of actors scurrying about trying to look like legions. But this surging Roman mob has real numbers, and its fickle allegiances to one demagogic political figure after another makes it genuinely frightening.

The satiric Trump references begin with the first appearance of Julius Caesar, depicted in Gregg Henry’s amusing performance as a preening Goldilocks who wears embarrassingly long ties, makes triumphal hand gestures and knows how to work the crowds. Our own crowd of complicit theatergoers roared with delight when he lowered himself into a golden bathtub. Here the hero was joined by his wife Calpurnia, deliciously played by Tina Benko in the slender, beautifully draped (by costumer Paul Tazewell) figure of a professional model speaking in the unmistakable accents of a native-born Slovenian.

The Trump analogy doesn’t hold up once Caesar is assassinated on his way to the Senate and is lauded in dueling eulogies, powerfully delivered here by Corey Stoll’s deeply sympathetic Brutus and Elizabeth Marvel’s cunning Marc Antony. In death, his open bleeding wounds on full public view, the tyrant has become a god. (But the insolent impersonation was fun while it lasted.)

The ever-present threat of dictatorship is visualized by set designer David Rockwell in the brutalist architecture of giant, grinding wheels of government. Kenneth Posner’s aggressive lighting and Jessica Paz’s discordant sound effects provide no comfort from the din of the mob. And lest we miss the message, the spotless white togas normally worn by the intellectual elite like Cicero the orator (Edward James Hyland) are all but eclipsed by the black trenchcoats of the conspirators and the intimidating black military uniforms worn by the ever-present army.

Call it a populist democracy, but don’t underestimate the muscle of a mob that can erupt into violence and claim the lives of honest men like Cinna the Poet (a brief but moving appearance by Yusef Bulos), sadly mistaken by a wild-eyed mob for Cinna the conspirator (Christopher Livingston).

The instigators of violence are exceptionally well cast and forcefully played by theatrical strongman John Douglas Thompson as Cassius, chief among co-conspirators including Decius (Eisa Davis) and Casca (Teagle F. Bougere). But of them all, only Brutus seems honestly patriotic in his fears of Caesar’s demagoguery. The rest look like ambitious Washington politicians holding a convention and/or vacation in Rome.

The most dangerous villain in the piece, though, is the rampaging Roman mob, its allegiances flapping like a weathervane, its hatreds quickly stoked, its rages easily redirected to perceived enemies. Although no one among the rabble actually chants “Lock her up!” or “Trump that b—!” or “Kick him out!,” the echo of mobs past hangs in the air.