My talk will focus on the biography of Isaac Nakhman Steinberg, protagonist of the October Revolution and later leader of Jewish Neo-Territorialism (Freeland League for Jewish Territorial Colonization). Steinberg will serve as a paradigmatic example for the transnational activism of a global subject that was informed by an attitude of rooted cosmopolitanism. On the one hand, the Socialist Revolutionary and avowed internationalist Steinberg struggled for the liberation of all mankind from social and political oppression which he thought emanated mostly from nationalism and the homogenizing and excluding tendencies of the nation state. On the other hand, Steinberg who remained an observant Jew and Yiddishist all of his life also fought for the preservation of cultural sovereignty of East European Jewry. In the light of the Shoah Steinberg pleaded for a continuity of the transnational diaspora-culture of the remains of East European Jewry in some other part of the world. In this respect, his approach fundamentally differed from Zionism on the one hand and radical assimilation on the other hand. Steinberg’s rootedness was in no way a particularistic antipode to his cosmopolitan universalism. Rather, his identity as a rooted cosmopolitan was informed by a synthesis of advocating Jewish cultural particularities and his “loyalty to all of humanity” (Anthony Appiah).