Obligation to settle disputes peacefully
The peaceful settlement of international disputes is a fundamental principle of international law, and a direct corollary of the prohibition on the threat or use of force. Both principles feature prominently in the 1945 Charter of the United Nations (UN Charter). They have been repeated on many occasions, including the UN General Assembly's 1970 Declaration on Principles of International Law Concerning Friendly Relations and Co-operation among States in Accordance with the Charter of the United Nations and the 1982 Manila Declaration on the Peaceful Settlement of Disputes between States.
Prior to the 20th century there were many circumstances in which it was considered legitimate for States to use armed force to settle their international disputes. Gradually, however, as the power and efficiency of weaponry increased, public opinion began to shift and formal attempts began to limit the legitimacy of warfare as a tool for dispute resolution. Even prior to World War I, in 1899 and 1907, conventions were concluded at The Hague restricting the right to wage war and seeking to establish peaceful dispute resolution mechanisms. The Permanent Court of Arbitration was established through these treaties, providing a neutral forum in which States could settle their differences. The creation in 1919 of the League of Nations as a forum for international discussion and cooperation, and the Permanent Court of International Justice (PCIJ) as the first permanent judicial body to hear disputes between States, laid the foundation for a system of measures designed to ensure peaceful settlement of international disputes. However, the League of Nations was unable to prevent World War II, and following the war, the victorious States set about redesigning the system to overcome its major weaknesses. With the preservation of world peace as its foundation, the United Nations (UN) was formed.
Although UN member States are obliged to settle their disputes peacefully (UN Charter, art 2(3)), there is no specific requirement as to how a particular dispute must be settled. The UN Charter refers to a variety of mechanisms (art 33, below) and establishes the International Court of Justice (ICJ) as a forum for judicial settlement of international disputes. However, no particular method is mandated, and all depend upon the consent of the parties. In practice, a range of dispute resolution mechanisms are employed, from informal negotiations or diplomacy through to formal judicial proceedings.