This chapter examines five elements that play a central role in international legitimacy and constitute as such key elements of the international rule of law. They are: international community membership, right holding, hierarchy of right holders, rightful conduct and international authority. The determination of whether or not one is eligible for membership in the international system cannot be disconnected from the issue of right holding. Indeed, establishing who is and who is not a member of the international community, who is 'in' and who is 'out', relates to drawing the line between who is and who is not a right holder. The hierarchy among international right holders, itself associated with the hierarchy among fundamental principles, translates into the issue of the rightful conduct for the state, and the community of states, internationally. Equal rights and self-determination of peoples are compatible as well as are the principles of good faith and cooperation.