World War I dissolved international socialist solidarity through working-class nationalism

Evidence

The Second International succumbed to two forces: nationalism and revolutionary failure. With regard to nationalism, World War I found the majority of the workers of England, Germany, France, and Austro-Hungary willing to go to the battlefields under national leadership in order to fight against each other. International worker solidarity upon which socialism was based disintegrated. The socialist movement had failed to maintain the dichotomy between the interests of workers and the interests of capitalist ruling classes. State nationalism had triumphed as the dominant ideology of the working classes. — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 981