Karl Liebknecht (1871-1919) was a German socialist and a co-founder of the Spartacist League and the Communist Party of Germany. He became an exponent of Marxist ideas during his study of law and political economy in Leipzig and Berlin. As a lawyer, he often defended other left-wing socialists who were tried for offences such as smuggling socialist propaganda into Russia. He also wrote extensively against militarism. Liebknecht was an active member of the Second International and a founder of the "Socialist Youth International". He opposed Germany's participation in World War I, but following the party line he voted to authorise the necessary war loans in 1914. He was the only member of the Reichstag to vote against the war, the supporters of which included 110 of his own Party members. He continued to be a major critic of the Social- Democratic leadership under Karl Kautsky and its decision to acquiesce in going to war. His works include: Where Will Peace Come From? (1912), The Main Enemy is at Home! (1915) and Militarism (1917).