Non-state actors such as transnational social movements (TSMs) and international non-governmental organisations (INGOs) have had an increasingly high profile in global politics in recent years through advocacy and campaigning activities which have caused them to be of growing interest to scholars. However, two aspects of INGOs have not received much scholarly attention. The first relates to religious INGOs and the lack of research regarding how religion influences this significant sub-set. The second concerns internationalisation processes as there is little research on why clusters of loosely affiliated and often diverse national NGOs choose to combine to form large INGOs and the processes they go through. Using social movement theory as a methodological framework, this research addressed both points by carefully examining the genesis and developments of two large INGOs: firstly to identify how, and with what effect, religion interacted with other factors in their working practice; and secondly, to track the reasons for internationalisation and to determine the methods they used. Underpinning the research was a detailed review of how international relations, international development and social movement scholarship conceptualise religion and religious actors. This identified weaknesses in scholarship caused by the legacy of secularisation theory as it obstructs the ability to perceive the presence of religion and to understand what effect it may have. The research, therefore, concludes with two further contributions: the first are recommendations to improve religious literacy, by presenting a more contemporary way to conceptualise religion and religious actors; and finally, there are proposals for strengthening research methodology to enable the presence and influence of religion to be identified and incorporated into scholarly analysis.

This thesis conceptually and empirically explores how American foreign policy is changing under the domestic and international pressures brought about by social and cultural processes associated with the global resurgence of religion. It argues that in response to these pressures the American foreign policy establishment, and American diplomatic, foreign assistance and national security practices and institutions are gradually undergoing, since the end of the Cold War andespecially following September 11, processes of “desecularization”. In order to explain these foreign policy changes, this thesis develops a Historical Sociological (HS) approach to Foreign Policy Analysis (FPA). This theoretical framework allows investigating the complex causal mechanisms that have led to the emergence of “desecularizing actors” at the domestic American level, which are embedded or responding to macro-processes of religious resurgence at home and abroad. These desecularizing actors have mobilized at the micro-level to challenge at critical historical junctures what they perceive is the problematic secular character of American foreign policy intellectual traditions, state practices and policy-making structures. In order to advance their preferred inherently religious policy agendas, desecularizing actors have articulated a number of principled and strategic discourses, which enable them to successfully contest and renegotiate the boundaries between “the secular” and “the religious” in American foreign policy. This thesis draws from ongoing conceptual debates in the sociology of religion on desecularization and applies this concept to that of a state’s foreign policy. It unpacks how processes of desecularization have taken place at multiple levels and with different intensities across the American foreign policy apparatus. This thesis identifies two broad processes that relate to foreign policy desecularization. First, processes of “countersecularization” in terms of a growing entanglement between functionally differentiated American secular state practices and policy-making structures, and religious norms and actors. Second, processes of “counter-secularism” in terms of a progressive weakening of dominant secular epistemic, ideological, and normative ideational constructs among American policy-makers.