Religion is one of the most potent political forces in the contemporary world. The recent emergence of religious fundamentalism in many parts of the globe and the rise of religious conservatism in America are developments the political significance of which can hardly be exaggerated. Religion's power to stir passions, nourish social ideals and sustain mass movements makes it of obvious interest to students of politics. My concern is with contemporary liberal democracies and with the many questions we can ask about what role religion may play in their citizens' political decision-making. These are moral questions. The task of answering them falls to political philosophy.

These questions get their purchase because a society's commitment to liberal democracy entails certain moral commitments, commitments which are in some way normative for its citizens. Among the most important of these are commitments to liberty and equality, religious toleration, self-government, majoritarianism, the rule of law, and some measure of church–state separation. The precise content and implications of these commitments are matters of disagreement. Still, I shall assume they are clear and familiar enough that we can see how moral questions about religion and democracy arise, and compelling enough that we do not dismiss the questions out of hand.

Questions about the proper role of religion in liberal democratic decision-making fall into two broad categories. Some seize on the effect religion may have on political outcomes and ask how those outcomes square with the commitments of liberal democracy.