In ethnic and racial terms, America is growing rapidly more diverse. Yet attempts to extend racial threat hypotheses to today's immigrants have generated inconsistent results. This article develops the politicized places hypothesis, an alternative that focuses on how national and local conditions interact to construe immigrants as threatening. Hostile political reactions to neighboring immigrants are most likely when communities undergo sudden influxes of immigrants and when salient national rhetoric reinforces the threat. Data from several sources, including twelve geocoded surveys from 1992 to 2009, provide consistent support for this approach. Time-series cross-sectional and panel data allow the analysis to exploit exogenous shifts in salient national issues such as the September 11 attacks, reducing the problem of residential self-selection and other threats to validity. The article also tests the hypothesis using new data on local anti-immigrant policies. By highlighting the interaction of local and national conditions, the politicized places hypothesis can explain both individual attitudes and local political outcomes.