Sentenced to ten years for treason

On October 6, 1949, following a lengthy and highly publicized federal trial in San Francisco, Iva Toguri D'Aquino was convicted on one count of treason and sentenced to ten years in federal prison and fined $10,000. The trial, one of the longest and most expensive in American history to that point, rested largely on the testimony of Japanese witnesses who later admitted, decades afterward, that they had been coerced and coached by American prosecutors and occupation officials.

Toguri's defense argued that her broadcasts on The Zero Hour were largely comedic, harmless, and in some cases deliberately undermined Japanese propaganda goals by including subtle jokes recognizable to Allied servicemen. Nevertheless, the jury convicted her on a single count out of eight, related to a broadcast about the loss of Allied ships.

She was reportedly the first woman convicted of treason in the United States as a result of wartime broadcasting, and her case remains a landmark in the history of American treason prosecutions — one of only a small handful in the nation's history. The conviction devastated her reputation and citizenship status for decades, despite mounting evidence that surfaced later, including a 1976 investigative report and testimony recantations, that the case had been built on false witness statements.