There is a tension between democracy, which requires acknowledgment of human fallibility, and moral principle, which individuals normally hold with certainty. Partly for this reason, it is often difficult and uncomfortable to argue about moral values in a democratic public sphere. After exploring this tension, the essay identifies levels, strategies, and tactics for arguments about values, with illustrations of each. Although individuals may hold moral principles with certainty, public discourse about values necessarily must be inconclusive. This essay originally was presented at a 2009 conference on Bioethics, Public Moral Argument, and Social Responsibility held at Wake Forest University. It is reprinted here from the volume, Bioethics, Public Moral Argument, and Social Responsibility (Nancy M.P. King and Michael J. Hyde, Ed.), pp. 3–13 (New York: Routledge, 2012).