In a standard median voter model, low‐income immigration increases the size of the welfare state. Other research suggests evidence for a group‐interested voter model, which predicts that welfare will shrink with an increase in low‐income immigration. We contend that neither model accurately describes political reality after testing these theories with United States data from 1970 to 2010. We use a variety of measures for welfare and related public spending such as K-12 education, Medicaid, and unemployment insurance. Contrary to expectations from previous work focused on Europe, we find that the amount of immigrant‐driven ethnic and racial diversity does not have a significant effect on these spending areas, whether considered in total expenditure or per capita. This could be due to countervailing pressures from these two models of voter motivation or due to factors unrelated to immigration, such as differences in institutions.