International customs and the “public order” within a country need to be
respected by all kinds of subjects of international law. Among international customs,
violation of jus cogens and international customs are typical factors leading to illegality
of treaties or international laws. The cultural tradition, which guides the national
thinking of a country, and then affects the behavior and judgment of the state, has
become an objective factor in the process of the existence and development of the
existing international law, and has a direct impact on the formation of a country’s
values of international law.