It is at least a century since the law of nations last stood in such urgent need of rational analysis and revision. The whole international system is in the crucible of barbaric strife. Its reconstruction requires lastly more than merely restoring what the belligerents have destroyed. There is need for new concepts and the elaboration of new principles. There is work for constructive thinkers and for those who are bold in exposition. It would gratify Americans if their statesmen should assume the leadership in this great enterprise.