Lenin died in 1924 and Trotsky was soon knocked out of power. Stalin removed Trotsky from his position of War Commissar in 1925. In 1926 Trotsky formed an opposition to Stalin consisting of himself, Kamenev and Zinoviev. After Lenin's will was published in the New York Times, Stalin, suspecting Trotsky's role, had Trotsky deprived of his seat in the Politburo. In 1927, Trotsky attacked the Politburo's stance on China. Later, Trotsky and all other liberal opposition were expelled from the Party.

In 1928, Trotsky was deported to Russian Turkestan on charges of counter-revolutionary activity. In 1929, He was expelled from the Soviet Union and moved to Prinkipo. He stayed there for four years. In 1932, Trotsky's Soviet nationality was stripped away from him. He then bounced from France to Norway to Mexico, his final stop. On August 20, 1940, a Stalinist agent had Trotsky assassinated.

From a psychological perspective, one might presume that a contributing factor to Trotsky's decline was that he had the revolutionary personality. His whole life had been leading up to revolution and he's spent it fighting the whole way. Once the revolution was achieved, Trotsky could not readjust to his new position in life. Trotsky stayed in opposition essentially out of habit.

Another major cause of Trotsky's fall from grace is that before 1917, he was an outsider. The fact that he joined the Bolsheviks so late, and after criticising both the Bolsheviks and Mensheviks made quite an impression on other communists. To them, he felt like an intruder. When Lenin praised Trotsky for his performance in the revolution and it seemed he might have been Lenin's successor, the "old guard" party members were extremely jealous.

One giant conflict between Trotsky and Stalin was Stalin's idea of "Socialism in One Country." Trotsky subscribed to Marx's belief that communism could only succeed with a worldwide revolution. When it became evident that the workers of the world were not uniting to create a communist utopia, Stalin provided his isolated socialism theory in order to create a feeling of the security for all Communists. Trotsky would not go for this watered-down version, he continued his quest to spread the revolution. Stalin and the Upper Party members accused him of jeopardizing the cause.

Trotsky had a major character flaw that would plague him throughout his career and may be why he ultimately failed politically. He was too worried about his own image, and could be something of a softy. For instance, Lenin wrote Trotsky a letter which harshly criticized Stalin, but Trotsky didn't want to be a snitch so he didn't read it to the Communist Committee until after Lenin's death. By then, it could not be verified as truthful, and Stalin claimed it was all lies.