The model of the political realism in international relations conceived the relations between States as they are given in a space in which reigns the anarchy. Due to the international anarchic structure, the States have a special preoccupation with his security and true confidence between then are unlikely. The theory of democratic peace is one of the best known opposition to the anarchic necessity of the international system. Theorists of democratic peace argue that democracies donâ€™t make war one against each other. However, they still behave aggressively with respect to non-democracies, failing to observe international rules and treaties without a specific criterion for his noncompliance and, consequently, generating international instability and resentment. With theory of democratic peace, presented in The Law of Peoples, Rawls wants to give a response to political realism in international relations. The Rawlsean peace is one peace of peoples, which differ from States for presenting moral characteristics and limits on their powers of sovereignty. Peoples can grant other peoples reasonable conditions for cooperation (and are know that they are willing to act according to then). With time, peoples that living beneath such peace come to see it as a value and also develop mutual trust. Such peace is yet extended to non-liberal but decent peoples, thus including certain kinds of peoples that hardly would be considered democratic but have institutions that deserve to be respected. We argue that such inclusion makes Rawlsâ€™s democratic peace especially effective, because a large amount of peoples can be part of it, reducing the instability produced by resentment.