International relations theory (IRT) often ignores or has difficulty accounting for religion. Thus, the choice of “new” historians of human rights to focus on religious actors in the lead-up to the Universal Declaration of Human Rights (UDHR) is a noteworthy development. One important finding of this stream of scholarship is the crucial role played by Christian personalists in the cultivation of “human rights” discourse in the 1930s and 1940s. However, new school historiography carries assumptions consistent with IRT liberalism that weaken its analysis of religion in the origins of human rights. Most problematic is its dichotomous framework that pits liberal secularism against reactionary religion, which tends to minimize interpretive possibilities. By contrast, IRT constructivism is attuned to the emergence and socialization of norms as different cultures, religious traditions, and value systems interact. Various actors and social networks create, inter-subjectively, pragmatic consensus from positions of fundamental ideological difference. As such, this paper, following a constructivist impulse, uses the case of new school historiography of human rights to better understand the weakness and the promise of IRT in explaining the role of religion in international relations.