The past couple of years have been notable, if not for the toppling of some of our nation’s most prominent bastions of power then at least for granting us a peek at their underlying rot. The sexual-abuse allegations against Harvey Weinstein and the ongoing disclosures that have come in their wake, including those about Jeffrey Epstein, shed light on how powerful people are able to use a combination of money, influence, and force to silence victims who are weaker by dint of their gender, class, and age. And since 2017 the Trump Administration, thanks to its simultaneously shameless and chaotic style, has also provided us with glimpses of what man’s most corrupt and aggressive desires can look like.

But despite—or maybe because of—the distinct horror-show aspect of these revelations, many of us remain fascinated by power, not just in its collapse but in its moments of brazen triumph. The popularity of the HBO series “Succession,” currently in its second season and garnering the kind of dedicated viewership perhaps not seen since “The Sopranos,” is, I think, due to this knotty impulse. On the show, the four grown Roy siblings savagely battle one another, their father, and other extra-familial satellites for control of Waystar Royco, the family’s Murdochian media conglomerate. The will to power wrings the characters dry of any sympathy or fellow-feeling, and yet their tortured hunger also makes them interesting to watch: What won’t they do, and where won’t they go, to achieve domination over others?

I felt a similar kind of appalled fascination while watching “Where’s My Roy Cohn?,” Matt Tyrnauer’s excellent new documentary about the ruthless lawyer, which came out in select movie theatres on Friday. Cohn was born to a wealthy Jewish family in New York, and first came to prominence in 1951, in his twenties, as the remorseless prosecutor in the trial and execution of Julius and Ethel Rosenberg, for espionage. Soon after, he became the chief counsel to Senator Joseph McCarthy, whom he helped to hunt down alleged Communists and homosexuals in the government. Cohn was himself a closeted homosexual—who, as one of his cousins, the writer Anne Roiphe, says in the documentary, “would have done everything to hide it”—a fact that came into play during the Army-McCarthy hearings, in 1954. Early that year, the Army had accused Cohn of demanding a cushy posting for his close friend G. David Schine, a McCarthy aide who was drafted in 1953. In response, McCarthy and Cohn claimed that the Army’s allegation was made in bad faith, to retaliate against their attempt to uncover Communists among its ranks. For nearly two months in the spring of 1954, the Senate’s Subcommittee on Investigations sat to determine the case. During the hearings, representatives of the Army and members of the Senate committee insinuated that Cohn had lobbied the Army in this manner because he and Schine were, in the snide words of the committee’s counsel, “warm personal friends.” “He is one of my many good friends, sir, yes,” Cohn answers stiffly, in an archival clip of the hearing. When the courtroom’s audience chuckles unpleasantly at him, we see the strange incongruity between the young lawyer’s uncannily cold, staring eyes and his twisting lip. Humiliation and its corollary, the desire for revenge, are almost literally etched on his face.

Dave Marcus, another of Cohn’s cousins (there appears to have been no love lost within the family), notes that Cohn “loved power, he loved pulling the levers of power, and he got a taste for that very early in his career.” But one gets the sense that his willingness to intimidate and manipulate came not just from his youthful success but also from his intimate understanding that he himself, along with everyone else, was vulnerable to intimidation and manipulation. Cohn saw the world as a war zone in which one should follow a kill-or-be-killed approach, humiliating and besting others before one is humiliated and bested oneself. His combination of cruelty and vulnerability makes him magnetic as an object of study: it is both chilling and mesmerizing to watch the clips in which Cohn—almost unnaturally tan, his light-blue eyes glowing opaquely, his tongue darting restlessly in and out of his thin-lipped mouth—shamelessly spins falsehoods and half-truths. As Marcus says at one point, “He was totally ugly and totally charismatic at the same time.” Tyrnauer doesn’t make Cohn sympathetic—the film ultimately hews to the perspective of one interviewee, who says that to be in Cohn’s presence was to be “in the presence of evil”—but he does show him as complicated and fascinating.

But “Where’s My Roy Cohn?” isn’t simply a psychological profile. It also suggests that Cohn reflected the social and political conditions in which he operated. After his mortification in D.C., Cohn moved to New York, and into private practice, determined, as the lawyer and author Jim Zirin puts it in the documentary, “to claw his way to the very top echelon of American society, one way or the other.” The fact that he was welcomed with open arms by this echelon is telling of that milieu’s ability to overlook almost anything in the name of money and power. Nothing improved one’s social standing quite like a sharp suit and a good watch, a dry Martini and a bump of cocaine, a nudge to a judge or a called-in favor from a well-placed politician. In the three-plus decades that Cohn practiced in New York, he befriended and worked with the city’s leading mobsters (who were some of his most loyal clients), Steve Rubell and Ian Schrager, of Studio 54 (also his clients, and the subjects of a previous, very good documentary by Tyrnauer), Barbara Walters (who, the documentary suggests, served as his sometime beard), Andy Warhol, Halston, Norman Mailer, Ed Koch, the Reagans, and, perhaps most unsurprisingly, Donald J. Trump.

In the early eighties, Trump was his mid-thirties and looking to make his way from his father’s outer-boroughs empire to the inner sanctum of the Manhattan real-estate world. Cohn became his lawyer and fixer, teaching him his methods. Cohn always attacked and never apologized, stopped at nothing to reach his aims, confused and distracted his opponents by abruptly changing the terms of the conversation, and lied and cheated without compunction. (Roger Stone, another protégé of Cohn’s and a Trump adviser, amusedly recounts Cohn’s denial, at one point, of a very obvious, very bad face-lift.) “Those are the rules of war,” Stone—who, in January, was indicted by the special counsel Robert Mueller for obstruction, witness tampering, and false statements—says. (He has pleaded not guilty to the charges.) “Donald learned that from Roy. I learned that from Roy,” he adds.

Many of Cohn’s tactics clearly found their way into Trump’s arsenal. As Cohn grandly states in an archival interview in the documentary, Trump had always wanted to become “the biggest winner of all,” and the lawyer created a template that allowed him to achieve his goal. But Cohn serves as a precursor of more than simply Trump, the man. The President, like a fungus growing on a bed of decay, came to power amid an ethos of complacent and rabid self-interest that was already well established. The roots of this ethos reach at least as far back as America’s late-nineteenth-century Gilded Age, but reëmerged with new vigor in the sink-or-swim Reagan eighties, with Wall Street’s boom and the Administration’s reduction or elimination of social programs—a trend that has yet to be meaningfully reversed, and which continues to contribute to the ever-widening gap between the rich and the poor, “winners” and “losers.” In the documentary, Cohn is shown pointing out that his most prized artifacts were a thank-you letter from Trump and a picture of the Reagans, which he hung side by side in his office. In America, everybody loves a winner—even sometimes, shockingly, the losers. “Roy was an evil produced by certain parts of the American culture,” Roiphe says.

Cohn’s thirst for domination remained unslaked until the very end. Toward the conclusion of the documentary, we see a clip of the lawyer, not long before his death, appearing on Larry King’s show. At the time, he was ravaged by AIDS (a fact that he denied, claiming that he was suffering from liver cancer) and fighting a disbarment stemming from fraud accusations that had caught up with him. “Are you going to win this one, too?” King asks him, jovially. “You’re darn right I am, Larry,” Cohn answers, in a similarly jovial tone. With his blank, unblinking eyes, and his skin stretched tightly, frighteningly, over the carcass of his narrow face, he looks as though his will to power has finally reached its macabre conclusion.