MIA: Encyclopedia of Marxism: Glossary of Organisations
Meaning "minority" in Russian, the party was formed in 1903 from a split in the The Russian Social Democratic Labour Party (R.S.D.L.P), which created the Bolsheviki and Mensheviki parties.
During the 1905-07 revolution the Mensheviks opposed the working class and peasantry who were in open revolt. They believed that Socialism should only be achieved firstly through a bourgeois revolution (via reformism); following this revolution, they felt the working class and peasantry would then be able to revolt against the bourgeois, and establish Socialism.
After the successful bourgeois revolution of February 1917, most Mensheviks joined the provisional government, strongly subscribing to the theory of Stagism. After the October Revolution the Mensheviks opposed the Soviet government, primarily through bureaucratic lobbying, though some members later joined the white armies.
The radical wing of the Menshevik party, opposed to any coalition with the propertied classes, yet unwilling to accept the Bolshevik concept of the dictatorship of the working-class. Trotsky was long a member of this group, and also included Martov and Martinov.