this definition of national identity and suggests that the conceptualization of national identity includes both self-categorization and affect. Self-categorization refers to identifying with a nation and viewing oneself as a member of a nation. The affect part refers to the emotion a person has with this identification, such as a sense of belonging, or emotional attachment toward one's nation. The mere awareness of belonging to a certain group invokes positive emotions about the group, and leads to a tendency to act on behalf of that group, even when the other group members are sometimes personally unknown. National identity requires the process of self-categorization and it involves both the identification of in-group (identifying with one's nation), and differentiation of out-groups (other nations). By recognizing commonalities such as having common descent and common destiny, people identify with a nation and form an in-group, and at the same time they view people that identify with a different nation as out-groups. Social identity theory suggests a positive relationship between identification of a nation and derogation of other nations. By identifying with one's nation, people involve in intergroup comparisons, and tend to derogate out-groups. However, several studies have investigated this relationship between national identity and derogating other countries, and found that identifying with national identity does not necessarily result in out-group derogation. National identity, like other social identities, engenders positive emotions such as pride and love to one's nation, and feeling of obligations toward other citizens. The socialization of national identity, such as socializing national pride and a sense of the country's exceptionalism contributes to harmony among ethnic groups. For example, in the U.S, by integrating diverse ethnic groups in the overarching identity of being an American, people are united by a shared emotion of national pride and the feeling of belonging to the U.S, and thus tend to mitigate ethnic conflicts. From the point of International Law, sovereign national identity could not be subject of a treaty regulation or revision and any international treaty aiming to create or change the national identity of the sovereign state appears to violate the jus cogens rights of the nation. Treaty of revision of the national identity could be subject to termination under the Article 53 of the Vienna Convention on the Law of Treaties (that states: "A treaty is void if, at the time of its conclusion, it conflicts with a peremptory norm of general international law.").