The author of this article study a «two-uniform» position concerning the First World War of the one of leaders of Menshevism A. Potresov and his adherents which they had after February Revolution. This position combined a necessity of participation of the Russian Workers for the organization of national defense from the external enemy and a struggle for the conclusion of the just democratic peace. It has found the bright expression during the Unification Congress of Russian Social Democracy and the Kornilov’s action.