Time was when a nation, at the pinnacle of its might, asked itself the question: “In the relation of states, what is the right thing, which ought to be done, and what is the wrong thing, which ought not to be done?” It was Spain, a worldconquering power, which thus approached problems of policy in the light of rational choice and raised a crop of great and lucid minds who laid the foundations for what later became international law. But the particular principles to which these men looked for their answers have been proved inadequate, first in the practice of statesmen and then in the theory of jurists. Hopes that international relations could be ordered by the relatively simple moral rules which we recognize in the organized societies of men have been repeatedly and cruelly disappointed. The failure of this one great historic attempt to apply rational concepts to international relations has evidently made us despair of any possibility even of different rational systems in this field.