Yedinstvo or Edinstvo (Russian: Единство, meaning Unity) was a faction within the Russian Social Democratic Labor Party (RSDLP) between 1914 and 1917 and then a small independent party in 1917 and 1918. It was led by Georgi Plekhanov.
Plekhanov was a prominent Russian Marxist theoretician and journalist who lived in exile in Europe from the early 1880s until 1917. Although he was revered by Russian social democrats as the founding father of Russian Marxism, post-1900 he was gradually eclipsed within the RSDLP by younger leaders like Julius Martov, Vladimir Lenin, Alexander Bogdanov, and others. In the immediate aftermath of the split between Lenin's Bolsheviks and Martov's Mensheviks in August 1903, Plekhanov first sided with Lenin, but in late 1903 he went over to the Mensheviks. When the Bolsheviks and the Mensheviks further split in the wake of the Russian Revolution of 1905, Plekhanov formed a small faction within the Mensheviks known as "Party Mensheviks" (sometimes translated as "Pro-party Mensheviks"). He was critical of both the Bolsheviks and of most Mensheviks, whom he saw as concentrating on legal oppositionist work in Russia at the expense of revolutionary activities, using his newspaper, Dnevnik sotsialdemokrata (Diary of a Social Democrat), as bully pulpit.
Yedinstvo (literally: Unity, Russian: Единство, Lithuanian: Vienybė, Polish: Jedność) was a pro-Moscow and anti-Sąjūdis movement in the Lithuanian SSR during the Perestroika era. The goals of the movement were similar to those of the Latvian and Estonian Internationalist Movements, e.g. opposition to disintegration of the Soviet Union. Yedinstvo was supported by the Soviet military and the KGB.
In addition to representing the interests of Russophone immigrants, the organization had limited success among the Polish minority in Lithuania, many of whom preferred Lithuania as a member of the Soviet Union. Yedinstvo went as far as to support forming a Polish autonomous region in southeastern Lithuania. Some commentators suggested that the organization was more popular with the Polish minority than the Russophone minority of Lithuania, which might have surprised the Poles of Warsaw, then seeking a de-communization in Poland. Also, the pro-Moscow stance at times compromised the activities of more Lithuania-friendly Poles. At the election to the Soviet Congress of People's Deputies, two Poles were elected to that body, both pro-Moscow.