The Comintern forced America’s fragmented communist factions into a federated party.

Evidence

The American Communist Party was formed, then, during a time of some theoretical and ideological confusion. In point of fact, the movement in the United States had broken down into so many competing ideological factions in the early 1920s that it became necessary for the Comintern to impose order, uniting them into a single party. The party that resulted was dominated by foreign-language federations, the most powerful being the Russian and Finnish federations. The federations, though, were still often more concerned with the fortunes of the movement in their homelands than in America. Nationalism and nationalist rivalries were, consequently, a part of the party’s historical character. — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 996