Trial of Julius and Ethel Rosenberg and Morton Sobell: 1951

Gold implicated David Greenglass, who operated a machine shop in New York City with his brother-in-law, Julius Rosenberg. While in the army, Greenglass had worked in the Manhattan Project in Los Alamos, New Mexico, where the atom bomb was being constructed. Arrested, Greenglass confessed that he had accepted an invitation to engage in espionage presented by Rosenberg and his wife, Ethel, and conveyed to him by his own wife, Ruth, during a visit to New Mexico in 1944.

The Federal Bureau of Investigation (FBI) figured out that two of Julius Rosenberg's college classmates, Max Elitcher and Morton Sobell, had been part of a spy ring. Elitcher confessed, implicating Rosenberg and Sobell. The FBI also learned that Rosenberg had belonged to the Communist Party but apparently had dropped out of the party when his unit was dissolved in 1944.

Julius was arrested, then Ethel. Sobell, on a vacation trip to Mexico City with his family, was abducted by Mexican secret police, "deported" across the Texas border, and arrested.

Rather than espionage itself, the Rosenbergs and Sobell were charged with conspiracy to commit wartime espionage. The distinction was important. The standards for a conviction on conspiracy to commit wartime espionage are less onerous: Each conspirator may be liable for the acts of all the others, even without specific knowledge of them, and it is necessary only to prove that they conspired toward a given end, not that they succeeded.