Boris Souvarine (born Boris Konstantinovich Lifschitz and also known as Varine; 1895–1984) was an Imperial Russian-born French socialist and communist activist, essayist, and journalist.
He was born in Kiev, Ukraine. Souvarine's family moved to Paris in 1897, where he became a socialist activist from a young age. He trained as a jewellry designer and became an art worker.
He joined the Section Française de l'Internationale Ouvrière (SFIO) shortly before World War I. He was associated with Jean Longuet's left pacifist section of the party, and wrote for Longuet's paper Le Populaire, and later for Maxim Gorky's Novaya Zhizn. Although he initially supported France's participation in the conflict, he came to oppose it and, by the time of the October Revolution, he became a Bolshevik and one of the French activists of the Comintern.
He was subsequently a founding member and leading spokesmen for the French Communist Party (PCF), and its representative in the Executive Committee of the Comintern. In this role he was in regular contact with Leon Trotsky. When Trotsky became the target of vilification in the Communist Party of the Soviet Union (CPSU), Souvarine conveyed the PCF's support for Trotsky to the CPSU's Thirteenth Congress in 1924. He became associated with the communist opposition against Stalin. He was removed from his official roles within the PCF in early 1924, and was expelled by the Comintern in July. He became close to anti-stalinist communist figures in Paris (including Marcel Body, Christian Rakovsky and the writer Panait Istrati). In October 1925, Souvarine relaunched the Bulletin Communiste and in February 1926 he organised its supporters in the Marx-Lenin Communist Circle.
In the late 1920s, he remained active in the communist opposition, was close to Pierre Monatte and Alfred Rosmer, and wrote in La Révolution Prolétarienne. He shared some positions with the Left Opposition, as well with the so-called “Right Opposition”, but refused to take part in its international conference called by Heinrich Brandler and August Thalheimer in Berlin in 1930. The Marx-Lenin Communist Circle was renamed the Democratic Communist Circle (Cercle Communiste Démocratique) ; Bulletin Communiste was continued, and Souvarine also launched La Critique Sociale. His growing break with Trotsky was indicated by his analysis, by 1927, of the Soviet Union as "state capitalist", in contrast to Trotsky's designation of it as a "degenerated workers' state".
After World War II and during the Cold War, he moved towards a reformist politics, and increasingly adopted anti-Soviet positions. Souvarine was involved in a variety of organizations and journals of the anti-Stalinist left in France, publishing frequently on the Soviet Union, Joseph Stalin, and Stalinism. He also criticized Lenin. His criticisms of Stalinism were important sources for some less orthodox Trotskyists, such as C.L.R. James, who translated his book Stalin into English.
He died in Paris.