In 1981, James Buchanan published the text of a lecture entitled “Moral Community, Moral Order, and Moral Anarchy.” The argument in that paper deserves more attention than it has received in the literature, as it closely follows the argument made by Adam Smith in Theory of Moral Sentiments. Smith believed, and rightly, that moral communities—to use Buchanan’s words—are indispensable. Smith also believed that the system could be expanded to encompass norms that foster commercial society. Buchanan allows for the same possibility in his discussion of moral community, in some ways similar to Hayek’s “great society” norms. But Buchanan points out the dark possibility that moral orders can collapse, relegating interactions outside of small moral communities to moral anarchy. Buchanan’s contribution is an important, and unrecognized, link between Smith’s conception of propriety and Hume’s conception of convention.