Internationalist–defencist schism

Internationalist and defencist were the broad opposing camps in the international socialist movement during and shortly after the First World War. Prior to 1914, anti-militarism had been an article of faith among most European socialist parties. Leaders of the Second International had even suggested that socialist workers might foil a declaration of war by means of a general strike.

However, when war broke out in August 1914, the leaders of most European socialist parties rallied to the support of their respective countries, while a minority continued to oppose the war. Those in favour of their country's war efforts were variously called 'social patriots' or 'defencists'. Those opposed to the war called themselves 'Internationalists' and were often called 'defeatists' by their opponents.

The 'defencist' camp included many venerable figures of European socialism: Jules Guesde and Édouard Vaillant in France, Gustav Noske and Friedrich Ebert in Germany, Georgi Plekhanov and Ekaterina Breshkovskaia among the Russians. Leaders of the anti-war 'Internationalist' camp included Jean Jaurès (who was murdered for his anti-war stance in 1914), Karl Liebknecht and Rosa Luxemburg, and later also Karl Kautsky and Eduard Bernstein, in Germany, Iulii Martov, Vladimir Lenin, Viktor Chernov and Mark Natanson among the Russians. The anti-war socialists held two international conferences at Zimmerwald and Kienthal in Switzerland in 1915 and 1916.

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