Center-left social-democratic party which began as a secretive Polish-Lithuanian Marxist organization agitating for revolution. Party's leadership included the future head of the Soviet Secret Police, Felix Dzerzhinsky, and Lithuania's third President during the nation's brief period of independence (1920-1940), Kazys Grinius. Party merged with the Communist Party of Lithuania (renamed the Democratic Labour Party of Lithuania) and in 2012 its leader, Algirdas Butkevičius, became Prime Minister between 2012 to 2016. Party's parliamentary representation collapsed to just 13 members after elections held in 2020 [Lietuvos socialdemokratų partija (LSDP)].
