The idea of preventive diplomacy has captivated the United Nations ever since it was first articulated by Secretary-General Dag Hammarskjöld nearly half a century ago. Preventive diplomacy was presaged by Article 99 of the United Nations Charter, which allowed the Secretary-General to bring to the Security Council's attention threats to international peace and security. From the outset of the United Nations, Secretary-General Trygve Lie used the competence under this Article to gather information about situations, to establish contacts with those concerned, to send emissaries to look closely at situations, and to do whatever he could to head off or contain crises of international concern.

Secretary-General Dag Hammarskjöld knew that the United Nations could do little where there was a direct clash of interests between the superpowers during the Cold War. But he had in mind that, if the opportunity presented itself, he might be able to head off disputes between lesser powers and prevent them from the gravitational pull of the superpowers contest. Hammarskjöld put down markers on the practice of preventive diplomacy that are still very much in use today. He would decide if his efforts might be useful. Judgment was always involved; there was no automaticity about his involvement. He used representatives, whom he sent out on special missions or outposted in particular situations. He had in mind the deployment of a ring of representatives around the world.

Secretary-General U Thant moved Hammarskjöld's vision forward. His role in preventing a nuclear confrontation over the Cuban Missile Crisis must rank as the most spectacular example of preventive diplomacy in the annals of the United Nations. The UN archives contain dramatic materials on his efforts. I will revert to this later.

Secretary-General Kurt Waldheim continued the practice of preventive diplomacy. He had his successes in the border disputes between Iran and Iraq in the 1960s. He resorted to appeals in dangerous situations such as the 1973 Arab-Israeli War. He acted speedily in dispatching UN peacekeepers to contain and control that situation and was praised for his efforts.

Secretary-General Javier Pérez de Cuéllar acted successfully when he sent a discreet fact-finding mission to Bulgaria and Turkey in 1989 to help head off the deterioration of a dispute between the two countries. He called for the maintenance of a comprehensive global watch over threats to human security and welfare, and established a unit within the Office of the Secretary-General dedicated to the collection and analysis of information intended to help the Secretary-General provide alerts to the Security Council over situations that could threaten or breach international peace and security.

Secretary-General Boutros Boutros-Ghali took over shortly after the end of the Cold War when there were hopes of a new world order. In January 1992, the first-ever summit meeting of the Security Council requested a report from him on the future role of the United Nations in conflict prevention, peacemaking, and peacekeeping, which led him to submit the widely-acclaimed An Agenda for Peace. Boutros-Ghali practiced preventive diplomacy in cases such as the war between Eritrea and Yemen, and he supported the establishment of the first ever preventive deployment of UN peacekeepers in the former Yugoslav Republic of Macedonia.

Secretary-General Kofi Annan furthered the work of his predecessors and submitted three reports on the topic. He exercised preventive diplomacy successfully in the border conflict between Cameroon and Nigeria over the Bakassi Peninsula.

Current Secretary-General Ban Ki-moon has taken forward the practice of preventive diplomacy at the UN, and has given courageous leadership on the issue of global climate change that would be put into the category of preventive diplomacy. He has also submitted reports to the General Assembly on preventive diplomacy.

Historians acknowledge that the Cuban Missile Crisis was the most dangerous period in human history, when the world came closest to blowing itself up during thirteen days, from 16 to 28 October 1962. On 22 October, President John F. Kennedy announced that he had ordered a naval quarantine around Cuba to come into force on 24 October. American and Soviet naval vessels came into close proximity with a USSR submarine captain authorized, as is now known, to use nuclear weapons in defence of Soviet ships or in self-defence. The efforts of UN Secretary-General U Thant contributed greatly to defusing the crisis.

On 24 October 1962, in his address to the Security Council, U Thant stressed that what was at stake was the very fate of mankind. He called for urgent negotiations between the parties directly involved and informed the Council that he had sent urgent appeals to President Kennedy and Premier Nikita Khruschev for a moratorium of two to three weeks. On the part of the USSR, it would entail the voluntary suspension of all arms shipments to Cuba. On the part of the United States, it would entail the voluntary suspension of the quarantine, especially the searching of ships bound for Cuba. He also appealed to the U.S. President and the Prime Minister of Cuba to suspend the construction and development of major military facilities and installations in Cuba during the period of negotiation. He offered to make himself available to all parties concerned for whatever services he might be able to perform.

On 25 October 1962, Premier Khruschev wrote to U Thant accepting his proposal. President Kennedy also wrote that day that, while he appreciated the spirit that had prompted U Thant's message, the key to the solution of the crisis lay in the removal of the weapons from Cuba. Soviet vessels continued on their way to the quarantined waters. That very day, U Thant followed up with an urgent appeal to the two leaders. He was concerned that Soviet ships already on their way to Cuba might challenge the quarantine and produce a confrontation between Soviet and United States vessels, thereby destroying the possibility of negotiations. He therefore requested Premier Khruschev to instruct any Soviet ships already sailing toward Cuba to stay away from the interception area for a limited time. He also asked President Kennedy to instruct United States vessels in the Caribbean to do everything possible to avoid direct confrontation with Soviet ships. To each, he stated that if he received the assurance sought, he would inform the other side of it.

President Kennedy immediately accepted his proposal, contingent upon acceptance by the Soviet Government. Premier Khruschev also accepted the moratorium. He informed U Thant that he had ordered Soviet vessels bound for Cuba to stay out of the interception area temporarily. The next day, on 26 October, U Thant sent a message to Prime Minister Fidel Castro of Cuba informing him of the encouraging responses he had received to his appeals and asking that construction of major military installations in Cuba, and especially those designed to launch medium- and intermediate-range ballistic missiles, be suspended during the period of negotiations.

After the American and Soviet acceptances of U Thant's appeal, and during the crucial time he had obtained for them, President Kennedy and Premier Khruschev had their own exchange, through letters and messengers, and managed to reach an agreement on the formula that eventually ended the missile crisis. U Thant traveled to Cuba from 30 to 31 October 1962 for meetings with Cuban leaders. His visit was of importance inasmuch as it gave the Cuban leaders an opportunity to let off steam.

As the agreement was being consolidated, President Kennedy, in his letter of 28 October 1962 to Premier Khruschev wrote: "The distinguished efforts of Acting Secretary-General U Thant have greatly facilitated both our tasks." When all of the details had been settled and the crisis was over, the American and Soviet negotiators sent a joint letter to U Thant that said: "On behalf of the Government of the United States of America and the Soviet Union, we desire to express to you our appreciation for your efforts in assisting our Governments to avert the serious threat to peace which arose in the Caribbean area."
In 1987, Secretary-General Pérez de Cuéllar advocated that the United Nations system should maintain a Comprehensive Global Watch over threats to human security. This idea retains its value and should be revived. The United Nations has regional conflict prevention centres in some parts of the world, such as West Africa and Central Asia. It would be sound policy to establish more of these centres. Enhanced cooperation with regional and sub-regional conflict prevention mechanisms would also be worthwhile. It is also important to increase the staff of the Department of Political Affairs for preventive work.

The Secretary-General, spearheading the roles of the United Nations High Commissioner for Human Rights and of his Special Advisers on the Responsibility to Protect and the Prevention of Genocide, should foster diplomacy of democracy and human rights at the country level. This would facilitate conflict prevention.

The alleviation of extreme poverty is crucial, as is the empowerment of women. These are issues of strategy, as well as of justice. Enhancing human dignity is key to successful prevention.

The idea of preventive diplomacy is one of the great UN ideas that will be around for as long as the world organization exists; for behind it is a simple faith that whatever might be done to prevent crises or conflicts should be considered.
For further reading see: Bertrand G. Ramcharan Preventive Diplomacy at the UN. UN Intellectual History project, 2008; and the first UN Secretariat draft of An Agenda for Peace: Preventive Diplomacy, peacemaking and peacekeeping.