 Sleževičius remained active with the Lithuanian community, participating in the activities of the Lithuanian Society to Help Those Suffering from War, touring Russia as its representative.In 1917, Sleževičius, together with Felicija Bortkevičienė and other allies, broke away from the LDP to form the Lithuanian Popular Socialist Democratic Party.In 1917, Sleževičius, together with Kazys Grinius, joined the presidium of the newly established Supreme Council of Lithuania in Russia, based in Voronezh.