Leon Trotsky was a Bolshevik revolutionary and Marxist theorist. He was one of the leaders of the Russian October Revolution, second only to Vladimir Lenin. During the early days of the Soviet Union, he served first as People's Commissar for Foreign Affairs and later as the founder and commander of the Red Army and People's Commissar of War. He was also among the first members of the Politburo.After leading a failed struggle of the Left Opposition against the policies and rise of Joseph Stalin in the 1920s and the increasing role of bureaucracy in the Soviet Union, Trotsky was expelled from the Communist Party and deported from the Soviet Union. An early advocate of Red Army intervention against European fascism, Trotsky also opposed Stalin's peace agreements with Adolf Hitler in the 1930s. As the head of the Fourth International, Trotsky continued in exile to oppose the Stalinist bureaucracy in the Soviet Union, and was eventually assassinated in Mexico by Ramón Mercader, a Soviet agent. Trotsky's ideas form the basis of Trotskyism, a term coined as early as 1905 by his opponents in order to separate it from Marxism. Trotsky's ideas remain a major school of Marxist thought that is opposed to the theories of Stalinism. He was one of the few Soviet political figures who were never rehabilitated by the Soviet administration.