During World War I, he was very active under the flag of the Russian Red Cross, supplying food to the population of the fighting area. After the February Revolution of 1917, he was elected member of the Petrograd Soviet, where he used his influence to oppose Bolshevik propaganda. After the Bolshevik October revolution of 1917, He was elected member of the short-lived Constituent Assembly. As a member of the “Committee for the Salvation of the Motherland and of the Revolution,” and of the “Committee for the Defence of the Constituent Assembly,” he helped organize the struggle against the Bolsheviks in the ensuing Russian Civil War.