Abstract
This paper provides a defense of the following thesis: When there is reasonable disagreement over the design of morally necessary collective action schemes, it would not be reasonable to reject the authority of a democratic decision procedure to settle these disputes. My first argument is a straightforward application of contractualist reasoning, and mirrors T. M. Scanlon's defense of a principle of fairness for the distribution of benefits produced by a cooperative scheme. My second argument develops and defends the intuition that treating others morally requires respecting their exercise of moral judgment, or a sense of justice. I conclude by addressing the problem of disagreement over the design of the democratic decision procedure itself, and rebutting Jeremy Waldron's claim that democratic authority is incompatible with judicial review.