The growing opposition amongst the workers to the nightmare of the trenches put enormous pressure on the rank and file of the SPD. This emboldened the opposition not only within the Reichstag but throughout the party at large. By March 1916 a big minority refused to vote for the budget in the Reichstag. In June they fought against new taxes which “in the last resort serve the imperialist war which we will not tolerate.” This large opposition current won widespread support among the membership and took control of the Party organizations in Berlin, Bremen and Leipzig as well as other key industrial centres. At its first national conference in January 1917 this opposition – amorphous in composition – began to take a more organized form. For this they were promptly expelled, taking 120,000 into the new Independent Social Democratic Party of Germany (USPD or Independents).

Together in this new party were Marxists and revisionists. Revolutionaries and reformists were suddenly united in their general opposition to the war. Individuals like Karl Kautsky, Bernstein (who had moved to pacifism), Luxemburg, and Liebknecht were all members of the USPD. The Spartacist group constituted itself as an autonomous section of the new party. The Independents’ break with the SPD reflected a growing ferment, not only in the ranks of the SPD, but also in the ranks of the working class as a whole. Tens of thousands of militant workers, radicalized by the war and the effects of the February Revolution in Russia, entered its ranks. It became a classical centrist party, wavering between the ideas of Marxism and reformism.

Centrism, as defined by Leon Trotsky, “is composed of all those trends…that are between reformism and Marxism.” It arises from the process of transformation of the mass organizations, which does not develop in a straight line, but in a contradictory, dialectical, fashion. Centrism is an unstable phenomenon which straddles different material interests, from reformism – representing those of the labour aristocracy – to Marxism – representing the interests of the proletariat. What is of key importance is the direction in which the centrist party is developing. Due to its unstable character, it either goes over completely to revolution or reverts back to a classical reformist organization. The new USPD was moving towards a revolutionary standpoint.

By 1917 war weariness engulfed the mass of the German people. The soldiers in the front were sickened by the war, its bloodshed, brutality, poison gas, hunger and above all the incompetent general staff. Given the economic blockade surrounding Germany, the conditions of the working class in the factories had declined dramatically. Supplies of coal began to run out, and in the bitter winter of 1917-18 thousands of starving children died of cold. Rations were drastically cut. Adult consumption stood at 1000 calories a day and infant mortality increased by 50 percent since 1913. In the trenches loss of life was astronomical. The French calculated that between August 1914 and February 1917 one Frenchman was killed every single minute.