This article looks at the use of public health strategies to define political membership in the nation. I examine the use of the cordon sanitaire to mitigate the novel coronavirus in Qatar. I argue that it acts primarily as a boundary to map out zones of political exclusion, splitting those who are entitled to protection from disease from those who are not. Through an analysis of the logic, application, and history of the cordon sanitaire in Qatar and elsewhere, I argue that it is only a more explicit example of the ways that governments have applied public health measures such that they apportion exposure to COVID-19, protecting some while mandating exposure for others. Exposure, or protection from it, has become a means to spatialize power and territorialize the national imaginary, separating full members from those who are excluded and reduced to their economic function. © 2020 by the American Anthropological Association