A new era of international law begun with the Charter of the United Nations, because it established means to maintain international peace and security, and enforce international law. In that goal, the United Nations Security Council was created, but its strength and flaw are in the same place: its permanent members. Besides that, it is usually thought that the most important organ of the Organisation of the United Nations is not the UN Security Council, but the United Nations General Assembly, where every of 193 member states has one vote, which provides nominal equality. Nothing less essential are the United Nations Secretariat, which implements decisions of the General Assembly and the Security Council; and the International Court of Justice, which resolves disputes between member states and gives advisory opinions on questions raised by the General Assembly and the Security Council.
"Established in 1945 under theCharter of the United Nations, the General Assembly occupies a central position as the chief deliberative, policymaking and representative organ of the United Nations. Comprising all193 Members of the United Nations, it provides a unique forum for multilateral discussion of the full spectrum of international issues covered by the Charter. It also plays a significant role in the process of standard-setting and the codification of international law." [General Assembly of the United Nations]
"All members of the United Nations agree to accept and carry out the decisions of the Security Council. While other organs of the United Nations make recommendations to member states, only the Security Council has the power to make decisions that member states are then obligated to implement under the Charter." [United Nations Security Council]
The Security Council's permanent members, written in the original text of the UN Charter, were The Republic of China (Taiwan or ROC), France, the Union of Soviet Socialist Republics (USSR), the United Kingdom of Great Britain and Northern Ireland (UK), and the United States of America (USA). First change in the society of the permanent members of the Security Council was in 1971, when the People's Republic of China (PRC) assumed ROC's seat, causing the ROC to lose its UN membership. Second related change happened in 1991, when the Russian Federation succeeded USSR's seat in the Council. Also, worth noting is the Security Council membership expansion from 11 to 15 in 1965.
"TheSecretariatcomprises theSecretary-Generaland tens of thousands of international UN staff members who carry out the day-to-day work of the UN as mandated by the General Assembly and the Organization's other principal organs. The Secretary-General ischief administrative officerof the Organization, appointed by the General Assembly on the recommendation of the Security Council for a five-year, renewable term. UN staff members are recruited internationally and locally, and work in duty stations and on peacekeeping missions all around the world. But serving the cause of peace in a violent world is a dangerous occupation. Since the founding of the United Nations, hundreds of brave men and womenhave given their livesin its service." [United Nations]
The authority which function is to provide unbiased application of international law is the International Court of Justice, which was founded by the UN Charter, and began work in 1946 as the successor to the Permanent Court of International Justice. ICJ might pass unbiased decisions, but their realization is at least questionable because the Security Council needs to guarantee it. As Hans Kelsen wrote in his book Peace Through Law: "The sovereignty of states under international law translates into the legal authority of states under international law. We can say that a state is sovereign because it is subject to international law and not to the domestic law of any other state. To be sovereign means to be independent from other states." Thus, ICJ was designed in such thinking, but the protection of interests of the permanent Council members takes hold over international law.
So, the problem emerges when some of judgments and advisory opinions of the ICJ are in collision with interests of the Security Council's permanent members because they can put veto on things they disapprove anytime. This leads to situation in which the permanent members of the Security Council or just one of them can obstruct every decision of the ICJ which they don't like. The best-known example of such a flagrant defrauding of international law is the 1986 case, The Republic of Nicaragua v. The United States of America. ICJ ruled in favor of Nicaragua, but the ruling could not be carried out because of USA's position as Security Council's permanent member.
The Organisation of the United Nations contributed to preserving international peace and security in the past 70 years, although it did not succeed in stopping all wars. Thus, main topic of contemporary debates about UN is how the Organisation should be reformed to meet the new challenges with unverified solutions.