In 1917 he welcomed the February Revolution because it got rid of the Tsar's incompetent leadership. But Potresov's demand to continue the war effort at all costs alienated him from most Mensheviks. Even the Revolutionary Defencists who dominated the soviets kept him at arms' length. During preparations for the elections to the Constituent Assembly, Potresov threatened to withdraw from the RSDRP and head a separate list. Potresov vehemently opposed the October Revolution. In 1918 he withdrew from the RSDRP and joined the Union for the Salvation of Russia, a group uniting right-wing Mensheviks, SRs, and Popular Socialists. He later regretted this collaboration.