The Evolution Of International Norms

International norms are informal international institutions, there are self-enforcing by non-central authority in a diffusing way. The study of the evolution of international norms is of vital importance for the understanding of the origin of orders in the anarchical international society.From the perspective of rationalism and methodological individualism, and based on the motivation by which international actors comply with international norms, international norms can be divided into two categories, one type of international norm is that when expecting most of other actors will comply with the norm, then it is of the interests of any single actor to comply with it, this is named as international norms without opportunistic motivation in this article. Another type of international norm is that when other actors are supposed to comply with the norm, then it is in the actor's long-term interests to comply with it, but there exists opportunism temptation for the actors to deviate from the norm and pursue short-term interests, this is named as international norms with short-term interests temptation.This article discussed the evolution of these two kinds of international norms through two game theoretical models of coordination game and the repeated prisoner's dilemma game. The evolution of international norms without opportunistic motivation has following characters: it can be established through two different approaches, one is through the collective negotiation, and set up by conscious design, the other approach is through spontaneous evolution and the gradual accretion of precedent. After its establishment, it is easy for this kind of international norms to diffuse and remain in existence. This kind of international norms is self-enhancing, and it can persist even after the original factors which lead to the emergence of it disappeared. This type of international norms can be vanished through the follows approaches: The disappearance of the object to which it act on; the transformation of the game structure, so that it cease to be a coordination game;or it can be substituted by another coordination norm.International norms with short-term interests temptation has different evolution characters, its establishment and stability will be influenced by following factors: the possibility of cooperative norms'emergence increases with the increase of long-term interests of reciprocal cooperation; the possibility of cooperative norms'emergence decreases with the increase of short-term opportunism temptation; the possibility of cooperative norms'emergence increases if international actors care more about the futures. More over, if the expense is not high when there is no cooperative norm, then it is difficult for the emergence of cooperative norms. Since there is always opportunistic temptation, the emergence of this type of international norms is usually the result of the conscious efforts of related actors. Its persistence will take the persistence of credible deterrence against deviation as a precondition. There is not clear threshold for the diffuse of this type of norms. Its disappearance can be the result of many factors: one is the transformation of the game structure, which makes the original norms cease to be attractive to international actors; another situation is that although the game remains to be the prisoner's dilemma game, but the stability of the norms is influenced by the change of the payoffs in the game. There is still another one situation that, to comply with the original norm is not of the interests of the international actors any more, and the actors take some actions to avoid it, in this situation, the norm virtually doesn't work, although it still exists nominally.