To understand and appraise the United Nations in its twentieth year we must consider whence it came and where it has come. As Abraham Lincoln once so wisely said: “If we could first know where we are and whither we are tending we could better judge what to do and how to do it.” When the Charter was drafted, it was contemplated that the Great Powers would work out an acceptable peace which the United Nations could maintain. But a stable and acceptable peace—a consensus or modicum of common understanding on the basic principles of coexistence—was never established after the last world war. The Great Powers were in no position to cooperate to maintain a peace the terms of which they were unable to agree upon. Rivalry and conflict among the Great Powers led to a Cold War in which the adversaries lost sight of their common interest in peace and were prone to exploit their differences rather than to attempt to find means of composing them. Even apart from the Cold War the whole world was struggling to adjust itself to revolutionary political, economic, and social changes, and the adjustment in many areas was difficult, painful, and not altogether rational. There was widespread need of adjustment to the radically changed conditions of life which modern science and technology made possible. In many areas the striving for economic improvement was accompanied by movements to break the bonds of colonial rule and feudal and tribal relationships. The very survival of the United Nations under these circumstances attests to humanity's essential need of the United Nations as an instrument of international cooperation in a world which has become increasingly interdependent despite ideological, national, and cultural differences and outlooks.