During the February Revolution 1917, served in the Crimea. Popular in left-wing circles. Elected Deputy Chairman of the Sevastopol Soviet.
Commander of the Moscow military region, July-Sep. 1917. Major-general, 1917. Minister of War in the Provisional Government, 12 Sep.
1917. Demanded a separate peace for Russia. After his demand was rejected, sent on sick leave (practically resigned), 4 November 1917. Arrested by the Bolsheviks as an SR, 1918.
Joined the Red Army, 1919. High general staff posts during the Civil War. Thereafter professor at the Frunze Military Academy and other military educational establishments.
Wrote on tactics and military history. Left memoirs which were published in 1959.