Marxism’s economism forced the conclusion that nationalism was a backward, diversionary ideology.

Evidence

In the characterization of nationalism by Marxist theorists, presumably general principles of historical or objective nature were opposed to factors of special and short-term significance; but every debate responded to contemporary events by attempting to encompass the evidences of new sciences, new events, and the effects of immediate political and ideological struggles. And the antagonists often reversed their opinions with the appropriate shows of “new understanding.” Unfortunately, the relegation of consciousness in the Marxian logic to a reflex of the relations of production and the frequent preoccupation with capitalism as a system determined by its own objective laws and the motivating force of historical change, most consistently led to the conclusion that nationalism among working classes was contrary to the historical movement of modern societies. In this sense, nationalism was a backward ideology, often a means of deflecting the class struggle into imperialist wars, and in any case not a fit subject for serious study in its own right since it was merely a politically convenient conduit of other forces and interests. — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 361