Trotsky's Unassailable Position: In 1924, Trotsky was a hero of the October Revolution, creator of the Red Army, and architect of victory in the Civil War. Lenin had asked him to denounce and remove Stalin.
Old Bolsheviks' Jealousy and Resentment: Trotsky provoked jealousy and resentment among Old Bolsheviks, particularly Stalin, Kamenev, and Zinoviev.
Lessons of October (1924): Trotsky's book highlighted his key role in the success of the revolution, including the timing and location of events. He did not explicitly attack Kamenev and Zinoviev, but the book embarrassed them.
loyal and unambitious, undangerous by Zinoviev and Kamenev. control of the party machine: key roles as Commissar for Nationalities, Politburo, Orgburo, Secretariat, Liaison with Cheka, Head of Rabkrin, and General Secretary.
Lenin Enrolment (1922-1924): The increase in party membership from 300,000 to 600,000 bolstered Stalin's patronage powers.
Stalin's Fall from Favor with Lenin: Stalin's brutal suppression of the Georgians and rudeness to Lenin's wife strained his relationship with Lenin. Nonetheless, other leaders were more concerned about Trotsky.