moderate political leader, statesman, and prime minister who was instrumental in rebuilding the Finnish Social Democratic Party after his country's civil war of 1918. Thereafter he consistently opposed Soviet demands for concessions and inroads on his country's independence.

Tanner entered the Finnish Parliament as a member of the Social Democratic Party in 1907. In the 1918 civil war, he opposed the Social Democratic alliance with Communist forces, and, after their defeat, he helped reconstitute his party along democratic parliamentary lines. In addition to serving as prime minister in 1926–27, Tanner served as finance minister several times during the interwar period. At the outbreak of the Winter War of 1939–40, he became foreign minister and supported his government's hard line against Soviet demands. Holding cabinet posts throughout World War II, he largely consolidated the Finnish working class behind the war effort and suffered imprisonment thereafter on Soviet insistence. Released in 1949, Tanner returned to Parliament as a Social Democratic leader.