The trial of Ethel and Julius Rosenberg begins in New York Southern District federal court. Judge Irving R. Kaufman presides over the espionage prosecution of the couple accused of selling nuclear secrets to the Russians (treason could not be charged because the United States was not at war with the Soviet Union). The Rosenbergs, and co-defendant, Morton Sobell, were defended by the father and son team of Emanuel and Alexander Bloch. The prosecution includes the infamous Roy Cohn, best known for his association with Senator Joseph McCarthy.
David Greenglass was a machinist at Los Alamos, where America developed the atomic bomb. Julius Rosenberg, his brother-in-law, was a member of the American Communist Party and was fired from his government job during the Red Scare. According to Greenglass, Rosenberg asked him to pass highly confidential instructions on making atomic weapons to the Soviet Union. These materials were transferred to the Russians by Harry Gold, an acquaintance of Greenglass. The Soviets exploded their first atomic bomb (and effectively started the Cold War) in September 1949 based on information, including that from Greenglass, they had obtained from spies.
The only direct evidence of the Rosenberg's involvement was the confession of Greenglass. The left-wing community believed that the Rosenbergs were prosecuted because of their membership in the Communist Party. Their case became the cause celebre of leftists throughout the nation.
The trial lasted nearly a month, finally ending on April 4 with convictions for all the defendants. The Rosenbergs were sentenced to death row on April 6. Sobell received a thirty-year sentence. Greenglass got fifteen years for his cooperation. Reportedly, the Rosenbergs were offered a deal in which their death sentences would be commuted in return for an admission of their guilt. They refused and were executed.