The geographic concentration of disadvantage is a key mechanism of inequity. In the United States, the spatial patterning of disadvantage renders it more than the sum of its individual parts and disproportionately harms economically and racially marginalized Americans. This article focuses specifically on the political effects of Medicaid beneficiaries being concentrated in particular locales. After offering a framework for conceptualizing the community-wide consequences of such policy concentration, I analyze aggregate multiyear data to examine the effect of Medicaid density on county-level voter turnout and local organizational strength. I find that, as the proportion of county residents enrolled in Medicaid increases, the prevalence of civic and political membership associations declines and aggregate rates of voting decrease. These results suggest that, if grassroots political action is to be part of a strategy to achieve health equity, policy makers and local organizations must make efforts to counteract the sometimes demobilizing “place-based” political effects of “people-based” policies such as Medicaid.