Federal law and immigration policy create distinctions between citizens and non-citizens that threaten public health in the US. We rely on local health departments to prevent and contain the spread of contagious disease among the US population. But recent policy initiatives, including the attempt to redefine “public charge,” make the job of local health departments harder. In this article, I show how previous administrations protected the public health interests of state and local governments following welfare reform in the 1990s, compared with a new “public charge” doctrine that experience has shown produces “negative public health consequences” and, as DHS admits, could lead to “increased prevalence of communicable diseases, including among members of the U.S. citizen population.” In implementing a policy to discourage would-be immigrants who are poor, the federal government has lost sight of “population” health that is the domain of the local public health department.