Left communism is the range of communist viewpoints held by the communist left, which criticizes the political ideas and practices espoused—particularly following the series of revolutions which brought the First World War to an end—by Bolsheviks and by social democrats. Left communists assert positions which they regard as more authentically Marxist and proletarian than the views of Marxism–Leninism espoused by the Communist International after its first congress (March 1919) and during its second congress (July–August 1920).
Left communists represent a range of political movements distinct from Marxist–Leninists, whom they largely view as merely the left-wing of capital, from anarchist communists, some of whom they consider internationalist socialists, as well as from various other revolutionary socialist tendencies (for example De Leonists, whom they tend to see as being internationalist socialists only in limited instances).
Left communism breaks from Leninist ideas, believing that communists should not participate in capitalist parliaments or participate in conservative trade unions. However many left communists split over their criticisms of Leninism. Of left communists, the Council Communists criticized the Bolsheviks for their elitist party functions and emphasized a more autonomous organization of the working class, while others like Amadeo Bordiga emphasized political parties and criticized multi-party states.
Although she was murdered in 1919 before left communism emerged, Rosa Luxemburg has heavily influenced most left communists, both politically and theoretically. Proponents of left communism have included Amadeo Bordiga (1889–1970), Herman Gorter, Anton Pannekoek, Otto Rühle, Sylvia Pankhurst (1882–1960), and Paul Mattick (1904–1981).