What drives continuity and change in foreign policy? Developing a theory with the cases of multilateral development banks and UNESCO

This paper presents a theory of continuity and change in foreign policy developed through a plausibility probe of two cases: U.S. foreign policy in multilateral development banks (MDBs) and United Nations Educational, Scientific and Cultural Organization (UNESCO). Analyzing data of U.S. votes on 29,000+ individual development projects in MDBs from 2004 to 2023, we found remarkable policy continuity, demonstrating a (mostly) business-as-usual approach. In contrast, UNESCO is an example of foreign policy change under Trump. We explain our theoretical model starting with a bureaucratic lens, asserting that standard operating procedures (SOPs) in key agencies (i.e., Treasury) and bureaucratic inertia are key determinants of foreign policy continuity or change, followed by Congressional constraints, presidential salience, and American leadership and embedded liberalism. We calculate the probability of change for scenarios using estimated values, establishing the most likely conditions for continuity or change, and evaluating the plausibility of our theory through our cases.