Can a democratic society propose an account of its practices and institutions that is at once adequately robust to answer antidemocrats and sufficiently inclusive to ein the assent of citizens who disagree about philosophical, moral, and religious essentials? A robust theory will draw upon controversial philosophical premises, and will thereby fail to respect the deep pluralism characteristic of a free society. Anything less than a robust philosophical theory, however, will raise questions of why anyone should prefer democracy to mild oligarchy or peaceful tyranny.