The Zimmerwald Conference was held in Zimmerwald, Switzerland, from September 5 to 8, 1915. It was the first of three international socialist conferences convened by anti-militarist socialist parties from countries that were originally neutral during World War I. The individuals and organizations participating in this and subsequent conferences held at Kienthal and Stockholm are known jointly as the Zimmerwald movement.
The Zimmerwald Conference began the unraveling of the coalition between revolutionary socialists (the so-called Zimmerwald Left) and reformist socialists in the Second International.
Background
Socialist discussions on war
When the Second International, the primary international socialist organization before World War I, was founded in 1889, internationalism was one of its central tenets. "The workers have no Fatherland", Karl Marx and Friedrich Engels had declared in The Communist Manifesto. Paul Lafargue, Marx's son-in-law, in his keynote address at the International's founding congress called upon socialists to be "brothers with a single common enemy [...] private capital, whether it be Prussian, French, or Chinese". Despite this commitment to internationalism and the establishment in 1900 of the International Socialist Bureau (ISB) based in Brussels to manage the movement's affairs, the International remained but a loose confederation of national organizations, which considered political issues in national terms.
The French delegate Edouard Vaillant told the Second International's founding congress that "war, the most tragic product of present economic relations, can only disappear when capitalist production has made way for the emancipation of labor and the international triumph of socialism." Opposition to war became a pillar of its program, but the question of what to do if war broke out would preoccupy socialists throughout the International's history and was the most controversial question discussed among the International's leading figures. Domela Nieuwenhuis from the Netherlands repeatedly suggested calling a general strike and launching an armed uprising if war should break out, but his proposals failed. The Second International did not seriously address the question of how it intended to oppose war until its 1907 congress in Stuttgart, after the 1905–1906 Moroccan Crisis brought the issue to the fore. In Stuttgart, the French Section of the Workers' International (SFIO) suggested employing all possible means to prevent war, including demonstrations, general strikes, and insurrections. The Social Democratic Party of Germany (SPD) was strongly opposed to any mention of general strikes. As a result, the resolution the congress promulgated was contradictory. It called on workers to "exert every effort to prevent the outbreak of war by means they consider most effective," but eschewed resistance to war as impractical, in favor of organizing opposition. When the 1912 Balkan War threatened to escalate into a wider conflict, the socialists organized a special congress in Basel, not in order to debate, but to protest military escalation. Like the 1907 meeting, it failed to yield any agreement on what tactics to employ in order to prevent war.