In the decade before WWI the growing imperialistic contrasts necessitated that social democracy adopt a clear standpoint regarding the war and the imperialism connected with it. This did not involve only purely theoretical issues, but rather the need to form concrete tactics of social democracy in case of a possible military clash of arms that might involve the whole world. Another aspect was also the need to verify the power of the principle of »internationalism « in practice. The answer of unanimously adopted congress resolutions (Basel, 1912) was clear: it is necessary to employ all means to prevent the war; if, however, it was unavoidable, this should be used to propel a social revolution. But these resolutions were forgotten at the onset of war. They were replaced by the transition from an internationalistic to a socially chauvinistic position, which resulted in the breakdown of the Second International that was unable to realize its primary goal, the preservation of peace.