In the October 1973 issue of this Journal, John Orbell and Brent Rutherford published an article which sought to test the central thesis of Hobbes’ Leviathan. Although I shall try to show that as a piece of research it was fatally flawed, the authors deserve acclaim for their boldness, and for showing the way back to serious comparative government research in the Aristotelian manner. To test the basic principles of constitutions against the claims made for them is so obviously worthwhile that it is inexplicable and sad that their article stands virtually alone. In part its rarity reflects the unspoken assumption in modern political science that, after the behavioural revolution, anyone taking constitutions seriously was bound to be returning to the discredited legalism of the past. This overreaction has had its worst excess in political theory, for we seem all to have forgotten that political theory used to be an attempt to devise constitutional frameworks within which human nature would be led to produce the good life. As a theorist I hope we will return to that, and as an empirical researcher I hope we take up Orbell and Rutherford's lead and start to test such general constitutional claims. There are plenty of examples to go on with, starting perhaps with the claim that the United States Constitution is apt to ‘establish justice, insure domestic tranquillity, provide for the common defence, promote the general welfare, and secure the blessings of liberty’.