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The Allied intervention was a multi-national military expedition launched during the Russian Civil War in 1918. Its operations included forces from 14 nations and were conducted over a vast territory. The initial stated goals were to help the Czechoslovak Legions, secure supplies of munitions and armaments in Russian ports, and re-establish the Eastern front. After winning the war in Europe, the Allied powers militarily backed the pro-Tsarist, anti-Bolshevik White forces in Russia. Allied efforts were hampered by divided objectives, lack of an overarching strategy, war weariness and a lack of public support. These factors, together with the evacuation of the Czechoslovak Legion and the deteriorating situation compelled the Allies to withdraw from North Russia and Siberia in 1920, though Japanese forcesoccupied parts of Siberia until 1922 and the northern half of Sakhalin until 1925.
With the end of Allied support, the Red Army was able to inflict defeats on the remaining White government forces, leading to their eventual collapse. The Allied intervention and its foreign troops were effectively used by the Bolsheviks to argue that their enemies were backed by Western capitalists. The Bolsheviks were eventually victorious and established the Soviet Union.