Vattel formulated a well known principle of non-intervention known as Droit des gens ou principes de la noi naturalle. But this principle wasn’t frequently practised in some states in the nineteenth century.
The word Intervention literally means to interfere in the affair of another. In International Law, it means any act of interference by one country in the affair of another by force or any other means. Every state has an inalienable right to manage the affairs of it’s own. But, there are certain circumstances under which a state or group of states interfere with the affair of other state to compel to do something or refrain from doing something. Such interference is called Intervention.
Provisions of the U.N. Charter
Article 2, paragraph 4 of the charter implicitly prohibits intervention on the part of the individual state when it ordains the members to refrain in the international relations from the threat or use of force against the territorial integrity or political independence of any state .International Law however permits intervention, as dictatorial interference by one state in the affair of another state.
The principle of the United Nation is mentioned in Article 2.Article 2(1) states on “principle of the sovereign equality of all its members.” Article -2(3) states about peaceful settlement of international disputes. The important provisions are mentioned in the article-2(4) and article -2(7). Article 2(7) says about the establishment of the UN Jurisdiction in relation to the area of the discretion of sovereign states and thus draws the boundaries for UN intervention itself.
This article tells about the state abstain in the international relation from the threat or use of force. It is the clear charter provision against the intervention with the use of force.
The charter limits the permissible basis for an act of self-help. The Charter also says the organization  will ensure the observation of its principle by non-member for the maintenance of International peace and security.
The prohibition of intervention is a proposition that follows from one already provided of every state right to sovereignty, territorial integrity and political independence.
In 1986 of Nicaraguan case, the principle of non-intervention involves the right of every sovereign state to conduct its affair without outside interference. The court consider that it is part and parcel of customary international law, it requires political integrity to be respected. Further, the court stated the principle restricts all state or group of state to intervene directly or indirectly in the internal or external affair of other state.
Similarly, in another casethe court noted that the principle of non-intervention prohibits a state to interfere directly, with or without armed force in support of internal opposition within a state.
In the case, the International court considered only those aspects of the principle that appeared relevant to the dispute. Apart from the use of force, it is now needed of time to categorize what is, what is not prohibited by the principle, generally depend on society of state and their level of political development unless the United States sees fit to intervene, from its own perspective. The United States has to stay out from interfering in every matter of states being the superpower country.
The diplomats should not interfere in the internal affair of the state to which they are given work of. There is a greater emphasis on International relation been given in order to encourage and protection of human right in other states .
Whether there is an exception to the principle of non-intervention in the case of help needed to people seeking to exercise the right of self-determination remain controversial and was not dealt with in Nicaragua and whether circumstance supports the legitimate exercise of self defense.
Under Article, the exercise of the right of self defence is allowed till the security council has taken the steps necessary to maintain International Peace and security .there are many holding situations, which requires an immediate defensive response.
Thus it allows the state to decide the urgency of the situation and decide to act in defence but at the same time measures taken in exercise of self defence shall be immediately reported to the security council. But many states have said NO and said it as the misuse of power and illegitimate.
Role of General Assembly
As per the UN charter, it has provision that General assembly may consider and make a recommendation regarding matter related to the maintenance of international peace and security .the 1950 uniting for peace Resolution expressly grants the Assembly to make recommendation or enforcement  measures including military action, when the Security Council is unable to act. The general assembly is the remedy of authorization when the Security Council fails to act at its own accord. There is also a provision to call an emergency special session within 24 hours as a peaceful resolution. These powers are given to general assembly to determine these powers only after a happening of the breach of the peace or an act of aggression. The power of the General Assembly in the matter of peace and security has been confined to examine, discussion, occasionally, condemnation.
Exception to Article-2(4)
Article-2(4) restricts the state from using force in resolving their problem. Article-51 contains to individual and collective self-defense which provides the exception during unilateral use of force. This applies to the nature of what is meant by an armed attack. In this context inherited right is taken to depict the undesirable nature of this right to member and non-member in their defence against an armed attack.
In real the UN Charter does not clearly lay down a principle of non-intervention applying to the relationship between states, the principle is completely a general prohibition of the use of force in relation. The custom established has universal and imperative applicability in that it is consistently reaffirmed in a number of the treaty in General assembly.
Finally, the UN Charter strongly declare that the norm of non-intervention as the main governing rule of state relation and thus demonstrate the international society’s persisting conviction that the norm is the primary safeguard for the preservation of order and the peaceful coexistence among states.
Droit des gens ou principes de la noi naturalle ,1758,vol 1,para.37.
Art 2(4),United Nations Charter,1945.
Louis Henkin “Use of Force, Law and Us policy “in Right v. Might ,International Law and use of Force ,New York ,1991,p.38.
Malcolm N. Shaw ,International Law Cambridge ,Grotius publication Limited ,1991,p.686.
Article-2(6) ,United Nation Charter Act,1945.
Oppenheim’s International Law ,p.428.
Nicaragua v. United States (Merits) ICJ Reports (1986).
Mazian Jamnejad and Michael Wood.The Principle of non-intervention ,22,Leider Journal of International Law(2009) ,p.345-381.
ICJ Report 1986,p.106,para.20.
Armed Activities on Territory of Congo,DRC v. Uganda,ICJ Report, (2005) .
“Hereinafter “ Nicaraguan case.
See Supra at pg.7.
R.J Vincent ,Non-Intervention and International Order (priceton University press ,priceton ,1973).
Denza,Diplomatic Law (3rd ed,2008.p.465).
Art,51,United Nations,Charter Act,1945.
ICJ Reports (1986) p.194.
Louis Henkin ,How Nation Behave ,Law and Foreign Policy .New York ,Columbia University press,1979.p-140-149.
Judgement of the Military Tribunal at Numremberg ,1946,Trial of Germany major war criminal before the international military tribunal ,p.137.