Public international law establishes the framework and the criteria for identifying states as the principal actors in the international legal system. As the existence of a state presupposes control and jurisdiction over territory, international law deals with the acquisition of territory, state immunity and the legal responsibility of states in their conduct with each other. International law is similarly concerned with the treatment of individuals within state boundaries. There is thus a comprehensive regime dealing with group rights, the treatment of aliens, the rights of refugees, international crimes, nationality problems, and human rights generally [ Source: http://en.wikipedia.org/wiki/Public_international_law]

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The formation of the United Nations, for example, created a means for the world community to enforce international law upon members that violate its charter through the Security Council.