The united front is a form of struggle that may be pursued by revolutionaries. The basic theory of the united front tactic was first developed by the Comintern, an international socialist organisation created by revolutionaries in the wake of the 1917.

According to the theses of the 1921 Comintern congress: “The united front tactic is simply an initiative whereby the Communists propose to join with all workers belonging to other parties and groups and all unaligned workers in a common struggle to defend the immediate, basic interests of the working class against the bourgeoisie.” The united front allowed workers committed to the revolutionary overthrow of capitalism to struggle alongside non-revolutionary workers. Through these common struggles revolutionaries sought to win other workers to revolutionary socialism.