Since the beginnings of our nation, immigration and religion have served as two of the most powerful factors in the shaping of American identity. Religious freedom was enshrined as a national ideal in our earliest documents; James Madison, the principle author of the Constitution, stated that "religion and Government will both exist in greater purity, the less they are mixed together." ¹ This guiding principle has drawn millions of immigrants to the United States from all over the world, making America the religiously diverse nation it is today. This freedom of religion and openness to immigrants, however, has at times been obscured by racist and anti-religious prejudice. This website examines the role of the American Catholic Church in the debates over immigration policies that restricted entry into the U.S. based on ethnic background. Throughout the twentieth century, the U.S. Conference of Catholic Bishops and its forerunner, the National Catholic Welfare Conference, have fought for fairer laws and greater justice for immigrants. The documents presented in this site explore the changing perceptions on immigration in the twentieth century, as well as the Church's involvement in shaping immigration policy.