One of the first began in December 1950 with the prosecution of William Remington, a former Commerce Department employee and member of the War Production Board who had been charged with espionage following the defection of former KGB handler Elizabeth Bentley.

[19] While working in Irving H. Saypol's office for the Southern District of New York, Cohn assisted with the prosecutor's case against 11 senior members of the American Communist Party for advocating for the violent overthrow of the U.S. Federal Government, under the Smith Act.

Cohn's direct examination of Ethel's brother, David Greenglass, produced testimony that was central to the Rosenbergs' conviction and subsequent execution.

Greenglass testified that he had assisted the espionage activities of his brother-in-law by acting as a courier of classified documents that had been stolen from the Manhattan Project by Klaus Fuchs.

Greenglass would later change his story and allege that he committed perjury at the trial in order "to protect himself and his wife, Ruth, and that he was encouraged by the prosecution to do so.

[25][26] Distilling this consensus, Harvard Law School professor Alan Dershowitz wrote that the Rosenbergs were "guilty – and framed.

"[27] The Rosenberg trial brought the 24-year-old Cohn to the attention of Federal Bureau of Investigation (FBI) director J. Edgar Hoover.

With support from Hoover and Cardinal Spellman, Hearst columnist George Sokolsky convinced Joseph McCarthy to hire Cohn as his chief counsel, choosing him over Robert F.

[32] During the Lavender Scare, Cohn and McCarthy alleged that Soviet Bloc intelligence services had blackmailed multiple U.S. Federal Government employees into committing espionage in return for not exposing their closeted homosexuality.

[32] In response, President Dwight Eisenhower signed Executive Order 10450 on April 27, 1953, to ban homosexuals, whom he considered a national security risk, from being employed by the federal government.

[33] McCarthy and Cohn were responsible for the firing of many gay men from government employment, and strong-armed opponents into silence using rumors of their homosexuality.

"[35] Sokolsky introduced G. David Schine, an anti-Communist propagandist, to Cohn, who invited him to join McCarthy's staff as an unpaid consultant.

[1] He maintained close ties in conservative political circles, serving as an informal advisor to Richard Nixon and Ronald Reagan.

[44] While aligning himself with Republicans he simultaneously forged close ties to Democrats including New York mayor Ed Koch,[43] Secretary of State Carmine DeSapio,[39] and Brooklyn party boss Meade Esposito.

[55] The government alleged that Trump's corporation quoted different rental terms and conditions and made false "no vacancy" statements to African Americans for apartments it managed in Brooklyn, Queens, and Staten Island.

[56] In 1978, the Trump Organization was again in court for violating terms of the 1975 settlement; Cohn called the new charges "nothing more than a rehash of complaints by a couple of planted malcontents."

In October 1959, Cohn and a group of investors stepped in and gained control of the company, having bought 200,000 of the firm's 700,000 shares, which were purchased by his syndicate from the Cowens and on the open market over a three-month period prior to the takeover.

[61] Under Cohn's three-and-a-half-year leadership, Lionel was plagued by declining sales, quality-control problems and huge financial losses.

[62] In 1986, a five-judge panel of the Appellate Division of the New York State Supreme Court disbarred Cohn for unethical and unprofessional conduct, including misappropriation of clients' funds, lying on a bar application, and falsifying a change to a will.

[6] Despite the disbarment, many famous people showed up as character witnesses including Barbara Walters, Firing Line host William F. Buckley Jr. and Donald Trump.

[64] He participated in clinical trials of AZT, a drug initially synthesized to treat cancer but later developed as the first anti-HIV agent for AIDS patients.

[39] SI Newhouse, heir to the Condé Nast publishing empire, was Cohn's classmate at Horace Mann, and they remained lifelong friends.

[72] Cohn exchanged Christmas gifts with FBI director J. Edgar Hoover;[39] they attended parties with their mutual friend, Lewis Rosenstiel, founder of liquor company Schenley Industries.

During this period, Schine dated the actress Piper Laurie,[83] and he eventually married Hillevi Rombin, a former Miss Universe, with whom he had six children.

Prospective clients who want to kill their husband, torture a business partner, break the government's legs, hire Roy Cohn.

"[39] Maureen Dowd wrote in an article for The New York Times which described Matt Tyrnauer's film Where's My Roy Cohn?

"[92][93] Vanity Fair's Marie Brenner wrote in an article about Cohn's mentorship of Trump: "Cohn—possessed of a keen intellect... he could keep a jury spellbound.

Probably the best known is in Tony Kushner's Angels in America (1991), which portrays Cohn as a closeted, power-hungry hypocrite haunted by the ghost of Ethel Rosenberg as he denies dying of AIDS.

In the early 1990s, Cohn was one of two subjects of Ron Vawter's one-man show Roy Cohn/Jack Smith; his part was written by Gary Indiana.

[110][111] The film explores their friendship while Cohn is shown leading as actively LGBT lifestyle in New York City while forming a closer business relationship with Trump.