ABSTRACT
This study uses the doctrinal research method to evaluate the doctrine of self-defense as one of the fundamental principles of international law and as one of the exceptions to the prohibition of the use of force. To this end, this dissertation focuses on article 51 of the Charter of the United Nations, which establishes the right to legitimate defense in international law. The dissertation states that the provisions of article 51 among international law scholars have caused some controversy. These controversies have led to the fact that the scope of self-defense in international law is covered. The main problem with this investigation is that it is not clear whether Article 51 has revoked or preserved the doctrine of anticipatory self-defense
International right. This problem was exacerbated by the use of the terms “inherent right to individual or collective self-defense” and “armed attack” in article 51. Therefore, the question is: “Does international law expect a state to do nothing? Where is an objective? an imminent attack? The objective of this dissertation is, therefore, to examine the relationship between article 51 and the norms of customary international law and the circumstances under which the right of self-defense can be exercised. dissertation states that the doctrine of legitimate preventive defense violates articles 2 (4) and 51 of the Charter, which prohibits the unilateral use of force.In addition, both article 51 and customary international law establish different rules for the exercise of right to self-defense The rapporteur recalls the urgent need to amend article 51 to adapt it to the current global challenges for world security. The term “armed attack” must be clearly defined and the concept of collective self-defense under Article 51 should be deleted.
CHAPTER ONE
GENERAL INTRODUCTION
1.1 Background to the StudyÂ
 The doctrine of self-defence is one of the fundamental principles of International law.[1] The doctrine of self defence is common to all systems of law, and generally, as a legal concept, the  function and scope of Self-defence vary with the level of development of each legal system. Thus, International law which is characterized by lack of specialized machinery for the enforcement of International law and protection of the rights of member states has vested the individual member states the right to use force for the protection of certain essential rights.[2]
However, with the progress of international law and the effectiveness of its enforcement and protection procedures, there is a tendency to assign a duty of protection to a central authority such as the United Nations Security Council and restrict the law of Member States. individual to a unilateral action. Regardless of how effective the means of protection are provided by the central authority, it will be necessaryfor the protection of certain essential rights, and interests of the state to invest the states with  the right of self defence until the enforcement machinery of the United Nations (UN) comes to their aid.[3] It is difficult to envisage a legal system in which the prohibition of recourse to force has no exception in the form of the doctrine of self-defence. This is the justification of Self-defence in International law.
