When there is an infectious disease outbreak elsewhere, the public is quick and eager to applaud the government closing borders. In this process, the government likely disregards international law and prior expert judgments about the efficacy of such policies. Through a novel survey experiment conducted in the United States, we decompose people’s tendency to like border closures into theoretically informed constituent parts, such as a (dis)utility for violating international law, disregarding WHO recommendations and prior expert assessments, and the sheer preference for an open or closed border. Crucially, we oversample responds who might constitute a policy-relevant elite as their views might be more consequential in the policy formulation process. Our findings tell us about the sources of international cooperation in a public health crisis situation.