Today in 1940, Ramon Mercader, likely working on behalf of Stalin, murdered Leon Trotsky with an ice pick in his home outside of Mexico City. Trotsky died the following day.
Leon Trotsky was a Bolshevik revolutionary, who was assumed to be Lenin's successor until he was outmaneuvered by Stalin when Lenin fell ill in 1922 and then died in 1924. Trotsky, who had been exiled multiple times by many countries for his radicalism, was a fly in the ointment for Stalin.
Trotsky continued to agitate for a global Communist revolution, that directly undermined Stalin's idea of "Socialism In One Country." Trotsky was also critical of the Communist regime's suppression of democracy within the USSR, and hoped to diminish the ever-growing scope of the Communist Party's bureaucracy.
For these reasons, despite his crucial role in the early success of the Bolshevik revolution, Stalin began a propaganda campaign against him. He was expelled from the war commissariat, then the Politburo, and eventually from the Communist Party altogether in 1927. The following year, Stalin exiled Trotsky to Alma-Ata, a very remote part of Soviet-controlled central Asia. After a year of exile, he was exiled from the USSR entirely.
He was welcomed by Turkey, where he lived while penning his brilliant History of the Russian Revolution, and his memoir My Life: An Attempt at an Autobiography. He moved a few times subsequently, finally settling in Mexico. During Stalin's purges, Trotsky was ruled guilty of treason. An unsuccessful assassination attempt was made, by a group of machine gunners. It was Mercader, a Spanish communist in whom Trotsky and his family had placed their trust, who killed him.
Mexico sentenced Mercader to 20 years in prison, but the Soviets denied any involvement.
Trotsky is survived by a legacy of political sympathy, roughly described as Trotskyism, that continues to be a prominent voice in the global radical left.