Conflicts over citizenship and military service became a central issue in Italian-American relations in the early twentieth century. The United States and Italy founded their concepts of citizenship on two different bases, jus soli and jus sanguinis. As a consequence of this difference and the swelling number of Italian immigrants naturalized in America, the two governments' policies about naturalization and military service collided until 1918. The Italian government's policy put Italian Americans' loyalty to the United States in jeopardy, especially for men who wished to return to Italy for business or educational purposes. Thus, the study of Italian Americans' experiences in the context of the policies of both countries illustrates a key aspect of the relationship between the United States and Italy, both in terms of social experience and public policy.