Militaries are commonly deployed in response to domestic disasters. However, our understanding of this phenomenon remains incomplete, partly because the particulars of disasters make it hard to generalize about deployments used in response. This article leverages the COVID-19 pandemic’s global reach to systematically evaluate common hypotheses about when and how militaries are used to respond to domestic disasters. It presents original global data about domestic military deployments in pandemic response and uses it to assess common theoretical expectations about what shapes whether and how militaries are used in such contexts. The results suggest that decisions about whether to deploy militaries stem from the securitization of domestic disaster relief rather than being responses to specific disaster-related features, state capacity shortcomings, or other social or political factors, even as some of these elements shaped how militaries were used. The article concludes by outlining some hypotheses for future research about the impact of this securitization on civil–military relations.

How do militaries push back when they oppose civilian initiatives? This article analyses the sources and character of military dissent, focusing on the United States. It details the sources of military preferences over policy and strategy outcomes, emphasising the interplay of role conceptions with other material and ideational factors. It then presents a repertoire of means – tactics of dissent – through which military leaders can exert pressure, constraining and shaping civilians’ decision-making calculus and the implementation of policy and strategy choices. Empirically, it traces military dissent in the 1990s-era humanitarian interventions; the US's ‘War on Drugs’ beginning in the 1980s; and the Afghanistan surge debate in 2009. In so doing, the article contributes to a broader research programme on military dissent across regime types. It also expands scholars’ understandings of preference formation within militaries and illuminates the various pathways through which military dissent operates and potentially undermines civilian control.