This study tests competing hypotheses about popular support for European integration. It introduces antiimmigration sentiments as a key variable for understanding reluctance towards integration. Drawing on survey data, it is found that anti-immigration sentiments, economic considerations, and the evaluation of domestic governments are the strongest predictors of both support for integration and individuals' propensity to vote "Yes" in a referendum on the enlargement of the EU. When extrapolating the findings to future referendums on issues of European integration, it may be predicted that such referendums will result in a "No" outcome under the conditions of high levels of anti-immigration sentiments, pessimistic economic outlooks, and/or unpopularity of a government.
