The Social Democratic Party of Finland (SDP, , nicknamed: demarit in Finnish, ) is a social democratic political party in Finland. It is the third largest party in the Parliament of Finland with 43 seats.
Founded in 1899 as the Workers' Party of Finland (; ), the SDP is Finland's oldest active political party and has a close relationship with the Central Organisation of Finnish Trade Unions. It is also a member of the Party of European Socialists, Progressive Alliance, Socialist International and SAMAK.
Following the resignation of Antti Rinne in December 2019, Sanna Marin became the country's 76th Prime Minister. SDP formed a new coalition government on the basis of its predecessor, in effect continuing cooperation with the Centre Party, the Green League, the Left Alliance and the Swedish People's Party. Seven of the Finnish government its nineteen ministers are SDP members.
In September 2023, Antti Lindtman was elected leader of the party following Marin's resignation after the 2023 election.
History
The SDP was founded as the Workers' Party of Finland in 1899, with its first meeting being held from 17–20 July in Turku. The name was changed to the present form in 1903. The SDP was closely associated with the Finnish Trade Union Federation (SAJ), established in 1907, with all of its members also being members of the party. The party remained a chiefly extra-parliamentary movement until universal suffrage was introduced in 1906, after which the SDP's share of the votes reached 47% in the 1916 Finnish parliamentary election, when the party secured a majority in the parliament, the only time in the history of Finland when one party has had such a majority. The party lost its majority in the 1917 Finnish parliamentary election after independence from Russia and started a rebellion that escalated into the Finnish Civil War in 1918.
SDP members declared Finland a socialist republic, but they were defeated by the forces of the White Guard. The war resulted in most of the party leaders being killed, imprisoned or left to seek refuge in Soviet Russia. In addition, the process leading to the civil war and the war itself had stripped the party of its political legitimacy and respectability in the eyes of the right-wing majority. However, the political support for the party remained strong. In the 1919 Finnish parliamentary election, the party, reorganised by Väinö Tanner, received 80 of the 200 seats of the parliament. In 1918, former exiled SDP members founded the Communist Party of Finland (SKP) in Moscow. Although the SKP was banned in Finland until 1944, it was represented by front organizations, leading to the support of the Finnish working class being divided between the SDP and the SKP.
It became the life's work of Väinö Tanner to re-establish the SDP as a serious, governing party. The result was a much more patriotic SDP which leaned less to the left and was relatively isolated from its Nordic sister parties, namely the Danish Social Democrats, the Norwegian Labour Party and the Swedish Social Democratic Party. President Pehr Evind Svinhufvud's animosity kept the SDP out of government during his presidency from 1931 to 1937. With the exception of a brief period in 1926, when Tanner formed a minority government, the SDP was excluded from cabinet participation until Kyösti Kallio was elected President in 1937. During World War II, the party played a central role in a series of broad coalition cabinets, symbolising national unity forged in response to the threat of the Soviet Union in the Winter War of 1939–1940. The SDP was a member of the Labour and Socialist International from 1923 to 1940.