Realism, which is the dominant theory in current international studies, emphasizes that in a world with all kinds of political governments, and different moral, religious, political, and cultural and social beliefs and values, in the ruling Westphalian world, speaking of consensus, And reaching a just order acceptable to all nations (or states) seems impossible. Facing this theory, other theories such as the theory of the law of people of John Rawls (who is one of the most important thinkers of the 20th century) and the theory of egalitarian cosmopolitanism are placed. Rawls believes that even with the differences and disagreements, it is possible to reach a kind of international system or law that seems just and fair, and there is no need to propose impractical idealistic ideas, or necessarily the existence of a common value system, or moving towards . Egalitarians go even further and say that the world can agree on the principles of freedom and justice. The principles of justice and freedom should not stop at the water's edge and be considered specific to liberal democratic nations. The main question of this research is which of these theories' arguments are more justified. The main hypothesis of the article is that Rawls's arguments in John Rawls' theory of the law of nations are more justified than the other two theories. The method used in this research is the inference method of the best explanation.