The old adage — that historical drama says more about the time it was made than the time it depicts — has hardly ever been more true than with writer-director Aaron Sorkin’s “The Trial of the Chicago 7,” a riveting portrayal of events from 50 years ago that feels as vital as the latest news bulletin.

The Chicago 7, as we old people can tell you, were the leaders of the anti-war protests that arrived in Chicago for the 1968 Democratic National Convention — and ran headlong into Mayor Richard Daley’s police, which led to beatings, tear gas and arrests. The protesters chanted “The whole world is watching!” but it didn’t seem to matter, as the establishment Democrat, Vice President Hubert Humphrey, took the nomination, and then lost the 1968 election to Richard Nixon.

Nixon’s election, and the appointment of Attorney General John Mitchell (John Doman), were big reasons for the trial happening at all, Sorkin says here. Mitchell’s predecessor, Ramsey Clark, opted not to prosecute, because the evidence showed the rioting was mostly instigated by the Chicago cops. But Mitchell, holding to Nixon’s “law and order” platform and personally miffed at how Clark treated Mitchell during the transition between administrations, decides to bring the full weight of the Department of Justice on the activists’ heads.

The Chicago 7, before the trial, weren’t organizing with each other during the DNC convention; in fact, they often were at odds with each other, disagreeing on how to protest the Vietnam War. But soon the seven — college organizers Tom Hayden (Eddie Redmayne) and Rennie Davis (Alex Sharp), performative hippies Abbie Hoffman (Sacha Baron Cohen) and Jerry Rubin (Jeremy Strong), veteran peace activist David Dellinger (John Carroll Lynch), and lesser-known activists Lee Weiner (Noah Robbins) and John Froines (Danny Flaherty) — would share a title: co-defendant.

Added to the seven was an eighth: Bobby Seale (played by Yahya Abdul-Mateen II), a leader in the Black Panther Party, who was in Chicago for about four hours during the DNC. Seale explains in stark terms why he’s been lumped in with the others: A Black man will scare the jury into convicting.

Sorkin, who first sparked Hollywood’s attention with “A Few Good Men,” knows a good courtroom drama when he sees one, and the Chicago 7 trial provided enough excitement and strangeness for any writer. Consider the antics of Hoffman and Rubin in court, or the arguments between the Chicago 7′s lawyer, the irascible William Kunstler (Mark Rylance) and the hopelessly biased judge, Julius Hoffman (Frank Langella). Or there’s the moment that might make your blood run cold, after Seale’s impatience over the judge’s refusal to separate his case because Seale’s attorney is out sick.

Sorkin embellishes the court record here and there; if you’re a stickler for such things, watch Brett Morgen’s astounding 2007 documentary “Chicago 10.” Where Sorkin seems to add his playwright touches most is in the private meetings of Kunstler, co-counsel Leonard Weinglass (Ben Shenkman), and the defendants — where the tensions among the parties, particularly between the smart-alecky Abbie Hoffman and the straitlaced Hayden, reach the boiling point.

The cast is, top to bottom, breathtaking. Redmayne puts soul into the uptight Hayden, especially in a scene where Rylance’s wily Kunstler pushes him in a stinging mock-trial practice. Baron Cohen captures the anarchic humor of Abbie Hoffman, and replicates the nihilistic humor of his public appearances, which play like a stand-up comic’s routine. Abdul-Mateen (“Watchmen”) is a fiery presence, exploding with rage at the racism at the heart of the trial. Langella is ferocious as the doddering old fossil on the other side of the generation gap. Also worthy of note: Joseph Gordon-Levitt as the reluctant prosecutor and Michael Keaton as Ramsey Clark, the former AG who turns up at a key moment.

Sorkin reportedly researched the Chicago 7 for more than a decade, so it’s fascinating that his movie resonates at this moment in history. In scene after scene — of unarmed protesters dodging tear gas, of police mobs removing their ID and badges before they start cracking heads, of spiteful officials threatening free speech to score political points — we see echoes of what’s been on the news recently. We also get what the news coverage can’t show, which is the minds of the revolutionaries seeking to change the world and the establishment holding tight to power.

Much as Arthur Miller used the Salem witch trials of “The Crucible” to speak to the political witch trials of the McCarthy era, Sorkin in “The Trial of the Chicago 7” methodically and passionately retells this 50-year-old trial to call attention to what’s happening now. To borrow a phrase from Sorkin’s previous courtroom story, it’s time to see if we can handle the truth.

★★★★
‘The Trial of the Chicago 7’
Writer-director Aaron Sorkin is back in the courtroom, capturing the fire and fury of the anti-war activists put on trial for a 1968 “police riot.”
Where • Megaplex Jordan Commons (Sandy), Megaplex at The District (South Jordan), and Megaplex Legacy Crossing (Centerville).
When • Friday, Oct. 9, in select theaters; Friday, Oct. 16, streaming on Netflix.
Rated • R for language throughout, some violence, bloody images and drug use.
Running time • 129 minutes.