An analysis of decision-making in foreign policy and of the nature and function of moral norms leads to the conclusion that morality has little effect upon international politics. The nation-state system compels statesmen to place national interests above morality, so that in most cases moral norms serve rather than determine interests. In some imponderable ways moral norms influence foreign policy decisions because they form part of the environment in which the decision-makers function. But this influence is vastly outweighed by the compelling need to guarantee the nation's survival under all circumstances and by the possibility to justify almost any behavior designed to do this in moral terms. This possibility exists because the broad, general and abstract formulation of moral norms subjects them to the most varied interpretation in concrete cases and because the system of norms permits an expedient choice of any of its parts to suit a given situation. How a norm is interpreted and which norms are chosen under given circumstances is largely determined by the interests at stake. Thus, an improvement of international relations toward more cooperation and peacefulness is more likely to come from the development and awareness of common interests than from commonly held moral norms.