The Comintern’s authority initially failed to unify the American communist movement.

Evidence

Still, the vigor with which the Comintern pursued and institutionalized its hegemony had no immediate effect on the American communist movement. The history and organizations of revolutionary socialists and workers movements in the United States had been too disparate for any authority, domestic or otherwise, to impose cohesion and/or subordination. — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 986