The atomic spy case sat at the center of the era's fears. Julius and Ethel Rosenberg were convicted in 1951 of conspiracy to commit espionage for the Soviet Union on the testimony of Ethel's brother, David Greenglass; Judge Irving Kaufman, blaming them for the Korean War itself, imposed death sentences that shocked much of the world. A global clemency campaign — the Pope, Einstein, and millions of petitioners — failed, and the couple were electrocuted at Sing Sing on June 19, 1953, leaving two orphaned sons and a case that has never left American political memory.

Their co-defendant Morton Sobell, kidnapped back from Mexico to stand trial, received thirty years and served more than seventeen, including five at Alcatraz, while his wife Helen led the long campaign for his release. Decades later the documentary record complicated every side's certainties: Soviet cables and Greenglass's recantation indicated Julius had indeed run an espionage ring, while Ethel's conviction rested on testimony her brother admitted fabricating, and Sobell — who confessed in 2008 — had passed military, not atomic, secrets. The executions, though, remain what contemporaries called them: the Cold War's most irrevocable act of political justice.