By 1950 Cohn had become well known and had successfully prosecuted eleven members of the American Communist Party charged with sedition and treason. His work on the Alger Hiss case also highlighted his skills as a manipulative and cunning prosecutor. But it was Cohn's zealous prosecution of Julius and Ethel Rosenberg in 1951, in one of the most spectacular trials of the century, that made him almost a household name. The Rosenbergs were both found guilty of selling atomic secrets to the Soviets and were later executed.
Federal Burea of Investigation Director J. Edgar Hoover recommended Cohn to Republican Senator Joseph R. McCarthy, who had launched a zealous and reckless anti-communist crusade in 1950. By 1951, McCarthy was holding ongoing hearings intended to grill individuals about their past affiliations and sympathies in an attempt to expose communists of all stripes. He was in need of an effective attorney to assist him and hired Cohn upon Hoover's personal recommendation. Cohn did not disappoint. His penetrating questioning and aggressive tactics were a perfect complement to McCarthy's loutish behavior, and before long Cohn was McCarthy's chief counsel. Cohn thus became a key player in the agony that was McCarthyism. In 1954, when McCarthy overreached and made a fool of himself, Cohn quietly left his employ and began practicing law in New York City. Although Cohn's celebrity would fade in the years to come, he would always hold the dubious distinction of having aided and abetted the debilitating excesses of McCarthyism.
In private practice, Cohn enjoyed a storied career. His many high-profile clients included the Archdiocese of New York, Donald Trump, and Mafia kingpin John Gotti, among others. Cohn continued to be active in Republican politics and often acted as an informal advisor to Presidents Richard Nixon and Ronald Reagan. But Cohn's apparently unscrupulous practices made him the subject of numerous investigations in the 1970s and 1980s. The New York State Bar Association finally disbarred him just weeks before his death in Bethesda, Maryland, on 2 August 1986.
Paul G. Pierpaoli Jr.
Schrecker, Ellen. Many Are the Crimes: McCarthyism in America. Boston: Little, Brown, 1998.