Whether political obligation is the central or fundamental problem of political philosophy, as some have maintained (e.g., McPherson), may well be doubted. There is no doubt, however, that the history of political thought is replete with attempts to provide a satisfactory account of political obligation, from the time of Socrates to the present. These attempts have become increasingly sophisticated in recent years, but they have brought us no closer to agreement on a solution to the problem of political obligation than the efforts of, say, Thomas Hobbes and John Locke in the seventeenth century. Nor have these sophisticated attempts made it unnecessary to look back to earlier efforts to resolve the problem. On the contrary, an appreciation of the troublesome nature of political obligation seems to require some attention to its place in the history of political thought.