The Role of the Department of War in U.S. Disaster Relief: A Quantitative Analysis of Federal Emergency Management Agency Mission Assignments

Background When large-scale disasters exhaust civilian federal agencies’ assets, the U.S. Federal Emergency Management Agency can issue mission assignments to the Department of War (DoW) to leverage its unique, self-sustaining logistical and operational capabilities. Despite the DoW’s critical role, empirical analyses characterizing military involvement in civilian-led disaster response remain scarce, limiting the potential for proactive strategic planning. This study aimed to provide a data-driven baseline of DoW contributions to domestic disaster relief. Methods This study characterized DoW contributions to U.S. disaster response by analyzing 4,065 Federal Emergency Management Agency (FEMA) mission assignments issued between 2012–2024. Mission assignments were analyzed by geographic location, disaster type, event timing, personnel types deployed, and associated Emergency Support Function. Results The DoW supported 37% of all original FEMA mission assignments during the study period. Activity peaked during the 2017 hurricane season and the COVID-19 pandemic. Tropical cyclones and hurricanes in low-lying coastal states and island territories, and biological incidents in densely populated areas, were the primary drivers for DoW assistance. The DoW primarily supported Emergency Support Functions relating to Public Works and Engineering, Logistics, and Information and Planning activities. The U.S. Army Corps of Engineers was the most active entity, involved in 38% of all DoW-supported mission assignments. Conclusion As an essential federal partner in managing increasingly complex, large-scale disasters, a data-informed picture of the DoW’s contributions is vital for strategically optimizing operational planning and resource deployments to protect the health and well-being of the American public.