unhistorical:

June 19, 1953: Julius and Ethel Rosenberg are executed.

The Rosenberg trial began in March of 1951, and it ended in a guilty verdict and the following accusation by Judge Irving Kaufman, as he delivered the death sentence:

 I believe your conduct in putting into the hands of the Russians the A-Bomb years before our best scientists predicted Russia would perfect the bomb has already caused, in my opinion, the Communist aggression in Korea, with the resultant casualties exceeding 50,000 and who knows but that millions more of innocent people may pay the price of your treason. Indeed, by your betrayal you undoubtedly have altered the course of history to the disadvantage of our country.

Although few disputed the guilty verdict, the subsequent death sentence was met with much controversy. Jean-Paul Sartre called it a “legal lynching”, while Pablo Picasso referred to it as a “crime against humanity”; others, including Albert Einstein, Frida Kahlo, Bertolt Brecht, Fritz Lang, and even the Pope, voiced their opposition to the Rosenbergs’ fate as well, but after two years, President Eisenhower still refused to grant the couple clemency. 

On June 19, 1953, Julius and Ethel Rosenberg became the first ever American civilians to be executed for espionage.