Immigration remains a powerful and recurrent feature of American politics. Of the issues related to immigration, controversy over government policy for controlling illegal immigration occupies a central position in the debate. One increasingly important and prevalent type of control policy that has received little scholarly attention is worksite employment eligibility enforcement, otherwise known as E-Verify Laws. In the present article, we analyze variation in E-Verify policy adoption across the U.S. states, approaching the topic from multiple theoretical perspectives and testing several hypotheses pertaining to policy enactment. Our analysis points to the critical role of proportionate change in a state’s immigrant population, as well as the political activity of immigrant-employing industries, in leading to policy adoption. Despite the use of multiple objective indicators, we fail to find strong evidence supporting the hypothesis that economic distress within a state increases its likelihood of enacting E-Verify legislation. Overall, our analysis contributes to an underdeveloped area of immigration policy research and sheds light on an important contemporary immigration issue, while drawing broader conclusions concerning the factors influencing the emergence of anti-immigration policies more generally.