As the civil wars wound down and the health of his closest ally, Lenin, declined, Trotsky and his supporters in the Left Opposition (who opposed the moderation of the New Economic Policy
era and demanded a greater emphasis on rapid industrialization and international revolution) found themselves increasingly outmaneuvered by their enemies within the party leadership, notably the Old Bolsheviks Stalin, L. B. Kamenev, and G. E. Zinov′ev. Trotsky, in particular, made himself unpopular (in the party and at large) through his post–civil-war advocacy of Labor Armies and his denigration of the role of trade unions in the Soviet state, as well as his haughty and dismissive attitude to those he considered to be his intellectual inferiors—–that is, almost everyone. Moreover, although he had been encouraged by the ailing Lenin to put himself forward as leader and to quash Stalin, Trotsky declined (apparently fearing disunity of the party and in the belief that a Jewish leader would ignite an anti-Semitic, reactionary wave in Russia). Consequently, on 26 January 1925, he was replaced as People’s Commissar for Military and Naval Affairs and head of the Revvoensovet of the USSR by M. V. Frunze and was subsequently expelled from the Politbiuro (23 October 1926) and the Central Committee (23 October 1927). Meanwhile, he served (largely nominally) as chairman of the Main Concessions Committee of the USSR (May 1925–17 November 1927), member of the Presidium of VSNKh (May 1925–August 1926), and member of the Electro-Technical Directorate of VSNKH (from 1925).Trotsky’s reconciliation with Kamenev and Zinov′ev to oppose Stalin (the so-called United Opposition) in 1926 was easily contained by Stalin at the 15th Party Congress in 1927. Charged with factionalism, all leading members of the opposition were expelled from the party, including Trotsky (14 November 1927). The last of these events took place a week after Stalin had organized a display of “popular anger” at the opposition during a demonstration to mark the 10th anniversary of the October Revolution, during which stones were thrown at Trotsky by the crowd. To stifle any lingering influence he may have had, he was then banished to Alma-Ata in Kazakhstan on 17 January 1928, and forcibly exiled from the USSR on 16 January 1929.
After periods in Turkey (to 24 July 1933), France (to 18 July 1935), and Norway (to December 1936), Trotsky settled in Mexico from 9 January 1937, at the behest of the radical artist Diego Rivera. There, he rallied opposition to Stalin through the Fourth International, at the same time explicitly challenging the legitimacy of the Moscow-dominated Komintern, and wrote a series of major works, including
During the first great show trial in 1936 (“The Trial of the 16” or “The Trial of the Trotskyite–Zinov′evite Terrorist Center”), Trotsky was condemned to death in absentia, as the éminence grise behind the absurd charges of espionage and sabotage laid against the defendants. Trotsky’s guards and supporters subsequently thwarted several attempts to assassinate him, but his Mexican entourage was eventually penetrated by Ramón Mercader, an agent of the NKVD, who on 20 August 1940 attacked him with an ice pick as Trotsky was working at his desk. His blood soaked the manuscript of the book on which he was working: a biography of Stalin. He died in hospital in Mexico City the following day.