In the late nineteenth century, Italians and Eastern European Jews joined millions of migrants around the globe who left their countries to take advantage of the demand for unskilled labor in rapidly industrializing nations, including the United States. Many Americans of northern and western European ancestry regarded these newcomers as biologically and culturally inferior--unassimilable--and by 1924, the United States had instituted national origins quotas to curtail immigration from southern and eastern Europe. Weaving together political, social, and transnational history, Maddalena Marinari examines how, from 1882 to 1965, Italian and Jewish reformers profoundly influenced the country's immigration policy as they mobilized against the immigration laws that marked them as undesirable. Strategic alliances among restrictionist legislators in Congress, a climate of anti-immigrant hysteria, and a fickle executive branch often left these immigrants with few options except to negotiate and accept political compromises. As they tested the limits of citizenship and citizen activism, however, the actors at the heart of Marinari's story shaped the terms of debate around immigration in the United States in ways we still reckon with today.