WHAT have we learned? It is two centuries now since the American people commenced what even they appear to have understood as an experiment in liberty. In his essay in this volume, Martin Diamond, following the lead of Leo Strauss, observes that the men of the Declaration of Independence and of the Constitution were pursuing, were implementing what Hamilton called the “new science of politics.” There had been a crucial turn in political thought away from the earlier Greek assumption that the virtue of its citizens was the foundation of the state, and that society accordingly ought to focus on the inculcation of such virtue, and, of course, its further elucidation. Civic philosophy would be the basic science of such a society, with its teachings a kind of applied science. Such was the view that persisted thereafter for two thousand years, with generally indifferent results. Then came Locke and Montesquieu and others with a quite different view. They saw the object of society as the attainment of liberty for the individual, and judged that society accordingly ought to focus on the practicable arrangements that would establish and preserve that liberty. Diamond describes the Declaration as expressing the “political science of liberty” of that age, a science subsequently, and for the first time, fully elaborated in the Constitution.