In 1914, the outbreak of World War I led to a crisis in European socialism. Many European socialist leaders supported their respective governments' war aims. The social democratic parties in the UK, France, Belgium and Germany supported their respective state's wartime military and economic planning, discarding their commitment to internationalism and solidarity. The parliamentary leaderships of the socialist parties of Germany, France, Belgium and Britain each voted to support the war aims of their country's governments, although some leaders, like Ramsay MacDonald in Britain and Karl Liebknecht in Germany, opposed the war from the start.
