linguistic:paraphrasing
United front and theory of fascism

Trotsky was a central figure in the Comintern during its first four congresses. During this time, he helped to generalize the strategy and tactics of the Bolsheviks to newly formed Communist parties across Europe and further afield. From 1921 onwards, the united front, a method of uniting revolutionaries and reformists in the common struggle while winning some of the workers to revolution, was the central tactic put forward by the Comintern after the defeat of the German revolution.

Trotsky was a strong critic of the shifting Comintern policy position under Stalin which directed German Communists to treat social democrats as " social fascists ". Historian Bertrand Patenaude believed that the Comintern policy following the " Great Break " facilitated the rise of Hitler's party. Marxist theorist and economist Hillel Ticktin argued that Trotsky's political strategy and approach to fascism such as the emphasis on an organisational bloc between the German Communist Party and Social-Democratic party during the interwar period would very likely have prevented Hitler from ascending to political power.

Trotsky also formulated a theory of fascism based on a dialectical interpretation of events to analyze the manifestation of Italian fascism and the early emergence of Nazi Germany from 1930 to 1933.

After he was exiled and politically marginalized by Stalinism, Trotsky continued to argue for a united front against fascism in Germany and Spain. According to Joseph Choonara of the British Socialist Workers Party in International Socialism, his articles on the united front represent an essential part of his political legacy.