There are multiple generations of American voters who either never heard of Joseph McCarthy or have only a vague notion of who he was and what he did.

The junior Senator from Wisconsin during the 1950s is who he was. What he did was prey on American fears of outside threats, dominate the headlines by issuing blatant lies about those threats, blackmail government employees, and systematically assassinate the character of anyone who dared to oppose him. Despite his repellant personality, the obvious phoniness of his claims, and his odious smear tactics, McCarthy ran roughshod over American politics for years. His own Republican Party, including President Eisenhower, refused to stand up to him. Eventually the press and his own overreaching brought him disgrace, a premature death from alcoholism, and this entry in Webster’s Dictionary:

“McCarthyism: a mid-20th century political attitude characterized chiefly by opposition to elements held to be subversive and by the use of tactics involving personal attacks on individuals by means of widely publicized indiscriminate allegations, especially on the basis of unsubstantiated charges.”

If this sounds vaguely familiar, we can thank Roy Cohn, the brains behind both McCarthyism and Trumpism.

Cohn was a freakish piece of work. He grew up in the New York Democratic political machine but became notorious as the chief counsel for the ultra-right Republican McCarthy and joined the John Birch Society. He was a Jewish legal phenom who helped send the Rosenbergs to the gas chamber. Cohn was a homosexual who despised gays as weak and made his early career blackmailing closeted public servants and purging them from the government. He found himself exiled in disgrace after McCarthy’s implosion and then remade himself, with the help of many powerful liberal New York City Democrats and media celebrities, into one of the richest lawyers in Manhattan before being disbarred in 1986. Cohn, who never publicly admitted his homosexuality, died of AIDs that same year, contending up to the end that he had liver cancer.

Cohn took the blood sport of American politics and created a truly hellish, bare-knuckled version of it that is still winning 60 years later. Of all the countless shitheels who have careened through the political history of our republic, Cohn stands out as the most reptilian. Tony Kushner, who made Cohn a major figure in his play “Angels in America,” has another character in that work call Cohn “the worst human being who ever lived…the most twisted, vicious bastard ever to snort coke at Studio 54.” (For an excellent profile of Cohn, see the great Frank Rich’s recent article in New York Magazine.)

Cohn’s McCarthyism was vicious blitzkrieg of false charges labeling Americans (especially those who were political foes) as communist traitors driven by a simple set of rules: “Attack, attack attack—never defend—admit nothing, deny everything, launch counterattacks.”

Even after McCarthy’s downfall, Republicans sought out Cohn for advice. Cohn assisted Nixon (a kindred soul famous for his own ruthless smear tactics) with his highly successful “southern strategy,” in which Nixon wooed southern Democrats by making it clear that the Party of Lincoln would support white privilege and fight the Voting Rights Act. One of Cohn’s protégés was Roger Stone, who began his career as a Watergate dirty trickster for Nixon and Jeb Magruder. Stone and Stone met in 1976, when Stone was the youth director for Ronald Reagan’s first run at the Presidency. Cohn hosted Stone’s 30th birthday party.

Cohn also advised Ronald Reagan. Cohn met Paul Manafort in 1980 when Manafort was the southern campaign director for Reagan’s first run at the Presidency. Lee Atwater was Reagan’s political director, and he and Manafort resurrected Nixon’s southern strategy. Here is how Atwater described that strategy in a 1981 interview:

“You start out in 1954 by saying, ‘Nigger, nigger, nigger.’ By 1968 you can't say ‘nigger’—that hurts you. Backfires. So you say stuff like forced busing, states' rights and all that stuff. You're getting so abstract now [that] you're talking about cutting taxes, and all these things you're talking about are totally economic things and a byproduct of them is [that] blacks get hurt worse than whites. And subconsciously maybe that is part of it. I'm not saying that. But I'm saying that if it is getting that abstract, and that coded, that we are doing away with the racial problem one way or the other. You follow me—because obviously sitting around saying, ‘We want to cut this,’ is much more abstract than even the busing thing, and a hell of a lot more abstract than ‘nigger, nigger.’”

By the time George Herbert Walker Bush came around, Roy Cohn’s pupils were big political wheels in their own right. Stone, Manafort, and Atwater formed a Washington consulting firm that designed the racist Willie Horton ads that helped take down Michael Dukakis.

Roy Cohn and Donald Trump first intersected in the early 1970s, when Cohn represented Trump when Trump and his father were sued by the government for racists real estate practices. Predictably, Cohn accused the government of “Gestapo-like tactics.” Trump loved Cohn’s brawling combativeness, and the two became tight friends, lunching at the Four Seasons and partying at Studio 54. Trump has often called Cohn his most influential mentor. It was Roy Cohn introduced Roger Stone and Paul Manafort to Trump. Trump hired Black, Manafort, Stone, and Atwater to help him with his casino business. According to Roger Stone, Cohn admirer Richard Nixon was the first to propose that Donald Trump should run for President.

You can hear the ventriloquial influence of Roy Cohn every day in Trump’s endless blizzard of blatant lies. Democrats who don’t applaud him are “traitorous.” Obama spied on him. Lifelong Republicans Robert Mueller, James Comey, Andrew McCabe, and Rob Rosenstein are actually treasonous Democratic operatives. “There are thirteen known Democrats on the Mueller team,” brays Trump in classic McCarthy fashion, who promises to expose them “very, very soon.” (This is classic McCarthyish grandstanding.) Trump has constantly called for his political opponents to be imprisoned. And Trump’s continued refinement--with campaign manager Manafort’s help--of the “southern strategy” worked brilliantly in 2016. (If you want to know why Trump coddles white supremacists, take a look at where half of his Electoral College votes came from.)

This week the press revealed the latest example of Roy Cohn crawling out of The Great Sewer Below to once again guide Donald Trump’s hand. Instead of spending time determining what would replace the Iran nuclear deal once we exited it, it turns out that Trump aides were focused on hiring Black Cube, an Israeli private intelligence agency, to covertly dig up dirt on Ben Rhodes and Colin Kahl, key individuals from the Obama administration who helped negotiate the deal. Harvey Weinstein hired Black Cube to similarly smear the women who came forward to accuse him of sexual harassment.

The reign of terror enjoyed by Joe McCarthy and Roy Cohn made them feared and powerful. But neither managed to become President of the United States and the leader of the party that controls both houses of Congress. Trumpism is McCarthyism on steroids.