2Sadeqi Anahita, 1Mohaghegh Mohammad Taghi
1- PhD candidate of International Law, Law Faculty, Shahid Beheshti University, Tehran, Iran, Corresponding Author1
2- BSc of Law, Law Faculty, Mofid University, Qom, Iran
Until the First World War, there was no limit to the use of force in the international arena. Important achievements of the United Nations in the contemporary world and international law were the principle of the prohibition of the use of force, which restricted the use of force by countries has been. Hence, in the most important international legal document after the end of the Second World War, the United Nations Charter deals with this principle in article Article 2 (4). It is also worthwhile pointing out that the government and international organizations and the International Court of Justice have adopted the principle. According to this principle, in some cases, this principle is legitimized in some political units of force by various justifications, which are discussed in the article. As the United States considered it legitimate in the military strike against Afghanistan and Iraq, it declared it to be a pre-emptive, legitimate defense. The International Court of Justice has ruled that Article 2 (4) of the Charter is a general international law. It includes the prohibition of the use of force and the prevention of the threat of force. The International Law Commission also agrees with this view. The General Assembly also emphasized that the obligation to refrain from the threat and use of force in international relations is in the hands of all countries, not just the members of the United Nations.