This Article addresses a simple but important question: is culture a legitimate criterion for regulating migration and access to citizenship? While focusing on France, Germany, the Netherlands, the United Kingdom, and Denmark, I describe how these countries embrace illiberal migration policies which violate the same values they seek to protect. I then construct a two-stage set of immigration-regulation principles: at the first stage, immigrants would have to accept some structural liberal-democratic principles as a prerequisite for admission; these principles are not culturally-oriented but rather constitute a system of rules governing human behavior in liberal democracies. At the second stage, as part of the naturalization process, immigrants would be expected to recognize and respect some constitutional principles essential for obtaining citizenship of a specific state. I call this concept "National Constitutionalism." As the American debate on immigrant integration policy comes to a head, the European experience has some important lessons for U.S. policymakers.