“Subsequent practice” of member states of a treaty, as a possible way for making indirect amendments to that treaty, has been accepted by many authors and has been also recognized in judicial and arbitration decisions. This paper focuses on one aspect of this issue: has the prohibition on the use of force and threat, as a treaty and contractual commitment mentioned in the Charter of the United Nations, been ever amended and changed due to subsequent practice of member states of the treaty? To answer this question, existence of such a prohibition will be first studied in “contractual” terms. Then, various aspects of the prohibition and exceptions made to it in the text of the contract as well as possible impacts of subsequent practice of member states of the contract on this prohibition and its exceptions have been evaluated. To do this, the present paper avoids of in-depth discussion of the details of arguments provided by proponents and opponents of various doctrines which prescribe recourse to force. Instead, it reviews certain points about possible amendment and change in Para. 4, Article 2 or Article 15 of the Charter of the United Nations as a result of subsequent practice of member states.
)