The Expatriation Act of 1907 deprived scores of American-born women of their citizenship, because of their marriage to foreigners. Among its architects was James Brown Scott, the international lawyer who had just founded the American Society of International Law and would later achieve global influence through his leadership in the Carnegie Endowment for International Peace. In the mid-twenties, Scott would turn to feminism and strike up a collaboration with Doris Stevens and other veterans of the suffrage struggle in the National Woman’s Party (NWP). The resulting campaign would contribute to raise attention on the nationality rights of married women in the debates of international institutions. In turn, the pressure built internationally favored the recognition of full equality between men and women in US nationality law, achieved with the Dickstein-Copeland Act of 1934. This success came through the efforts of the women’s rights movement as a whole. Nevertheless, it showcased its divisions. The NWP campaign was based on the idea that women would achieve equality when all legal rules would make no distinction among the sexes; on the contrary, social feminists believed that for women to be substantially equal there should be protective legislation actively preventing their exploitation and discrimination, especially with regard to labor relations. In the matter of nationality, these two souls found a common goal: the shaky alignment that resulted would eventually be marred by ideological differences. The opposing conceptions of equality differed on their answer to a fundamental question: could women become fully equal members of society without tackling also other social and racial forms of injustice? The paper aims to highlight the complexity of the concept of equality within feminist political theory by contextualizing the trajectory from coverture to independent nationality and the interaction of domestic and international legal initiatives.