This first of two volumes introduces the tradition of social Catholicism, not only in its earlier realizations, but regarding how a contemporary renewal might address the crisis in which constitutional democracies and the postwar liberal order are under assault by populist and even neo-fascist movements that could soon usher in a frighteningly dark future unless a broad movement in defense of constitutional democracy quickly arises. In this context, some of the most influential voices among American Catholics are focused on criticizing "liberal democracy," on advocating a "postliberal order" and the establishment of a Catholic "integralist" state, or on insisting that abortion should be the primary sociopolitical concern for Catholics, treating these threats to democracy as largely irrelevant. This volume shows the rich tradition of social Catholicism, and how the Social Doctrine of the Church came to appreciate the key tenets of constitutional democracy. As Pope Benedict XVI wrote, this social doctrine leads us to "take a stand for the common good," to take the "institutional" or "political path of charity," to be "solicitous for" the "institutions that give structure to the life of society, juridically, civilly, politically and culturally." It engages some of the most influential contemporary Catholic thinkers and argues that they too should recognize the grave threats facing the human family and join in working to defend and renew our constitutional democracy.