The inherent weakness of the Socialist movement of Poland was fully revealed at the outbreak of World War I. No single Marxist group could claim for itself a really large following. All of them realized this and it was reflected in their tendency to join forces with groups having similar programs. The Polish Socialist party, or the PPS, formed a confederation with the non-Socialist parties which aimed at restoring Polish statehood in alliance with the Central Powers. The left Marxist groups of Kongresówka formed a loose grouping to pursue in common their radical, international anti-war policy.
Thus the outbreak of the war consolidated the two rival camps within Polish Socialism: that of pacifist and internationalist revolutionaries on the one hand, and that of the “Social Patriots,” on the other.