The United Nations Operation
in the Congo

written by Frances Storey '22
edited by Caitriona Keane '22 & Wendy Zhen '22

At the end of the Second World War, a new era of decolonization emerged, and imperial powers began to grant their colonies independence. The Congo, a mineral rich colony with competing ethnic rivalries, gained its independence from Belgium in June, 1960, but only weeks later, mutiny broke out in the army and tensions between the minority white and majority black citizens escalated into violence. In response, the southeastern province of Katanga seceded under the leadership of Moise Tshombe, the President of the province, and with support from the Belgian government. The post-World War II years also saw a rise in international organizations such as the World Bank, the International Monetary Fund, and the United Nations (UN). These organizations were quickly put under immense pressure to try and establish themselves in a world grappling with the aftermath of two world wars and colonialism. The actions taken by the UN in resolving the reintegration of Katanga with the rest of the Congo through the United Nations Operation in the Congo (ONUC), were crucial in legitimizing and establishing the UN as an effective international peacekeeping organization.

Facing international pressure amidst a wave of decolonization around the world, Belgium relinquished its colonial hold on the Congo in June, 1960 and signed a Treaty of Friendship with the new leaders of the Congo which promised a peaceful and collaborative relationship between the two governments. While Belgium promised on paper to relinquish official control over the entire territory, there was too much money at stake for them to leave quietly. In 1953, the Belgian Congo produced “86% of the cobalt, 60% of the tin, 64% of the diamonds, 53% of tungsten and zinc ores, and 34% of the copper” in Africa.[1] The Belgian government offered the Katangan President Tshombe financial support and employed a number of Belgian technicians, officers, and soldiers to help him run Katanga. Furious at the violation of the Treaty of Friendship, Congolese President Joseph Kasavubu and Prime Minister Patrice Lumumba appealed to the UN for support in ridding their newly independent country of external interference and reintegrating Katanga into the Congo.[2]

Dag Hammarskjöld, a Swedish diplomat, was the second Secretary General (SG) of the UN at the time of President Kasavubu’s appeal process, and he explained his interpretation of the UN Charter and his goal for the organization in his Annual Report of 1959-1960: “‘It is my firm conviction that any result bought at the price of a compromise with the principles and ideals of the Organization, either by yielding to force, by disregard of justice, by neglect of common interests or by contempt for human rights, is bought at too high a price.’” [3] Hammarskjöld approached the conflict with a strict appreciation for the rule of law and upheld the UN Charter. After receiving thetelegrams from the Congolese government requesting assistance, the Security Council passed a resolution on July 22, 1960 calling for Belgium to remove its troops from the Congo and authorized the SG to provide the Congolese government with necessary military assistance.[4] After the death of Patrice Lumumba, fears arose that a civil war would break out in the Congo. In response, the Security Council authorized that the UN “take immediately all appropriate measures to prevent the occurrence of civil war in the Congo, including arrangements for cease-fires, the halting of all military operations, the prevention of clashes, and the use of force, if necessary, in the last resort.” [5] In carrying out these orders, Hammarskjöld’s careful consideration of each element of ONUC’s mission showed impartiality towards the superpowers at a time of great tension. However, his actions weren’t favorable to everyone, and by the time of his death in November of 1961, the UN was facing a financial crisis and disagreements between member states on the proper actions

Hammarskjöld ’s successor, U Thant, focused on the financial issues that the UN faced and was successful in resolving the conflict in the Congo. Thant, a former schoolteacher, became the United Nation’s first non-European SG. He pledged his faith to developing the UN as “an indispensable centre for harmonizing the actions of nations in the attainment of our common ends.”[6] Thant took a firm stance against Katanga and supported the Congolese government’s attempts to reintegrate the secessionist state. As requested by Thant, the Security Council adopted Resolution 169 authorizing the use of force to remove any foreign military personnel that were not under the command of the UN Forces, and to prevent their return.[7] After various failed negotiation attempts and Tshombe’s repeated violations of agreements, the UN carried out Operation Grand Slam on December 28, 1962 ending with Tshombe’s surrender on January 15, 1963.[8] A combination of UN airstrikes and ground forces against the Katanga Gendarmerie secured the Katangan capital of Elizabethville and the remaining strongholds in the south, effectively ending the Katangan secession.

The ONUC was ultimately successful in its mission of reintegrating Katanga with the Congo, and demonstrating important lessons for future UN peacekeeping missions. In an era of rapid decolonization, Hammarskjöld and Thant were cognizant of setting precedents and recognizing secessionist states. ONUC was the first instance in which a UN peacekeeping mission turned into that of peace-enforcement with the deployment of troops and authorization of force. These authorizations would have been useless if they were not agreed upon and carried out by the member states. There was disagreement among the member states on how best to act, but despite these disagreements, the UN troops were overall a diverse representation of the member states and worked together successfully to resolve the conflict. At ONUC’s height in March 1963, there were 19,782 personnel that represented 22 countries.[9]

SGs Hammarskjöld, Thant and the Security Council helped legitimize the UN by showing that the UN was not solely acting in the interests of its most powerful members, but in the interests of every sovereign state. ONUC provided an early test for the UN and gave the organization an opportunity to show that it was capable of resolving international conflicts while balancing out the interests of the superpowers and the recently decolonized member states. SGs Hammarskjöld and Thant guided the UN through this conflict and established it as an effective peacekeeping organization.

[1] UN “Review of Economic Activity in Africa: 1950-1954” Supplement to World Economic Report. (New York, 1955).

[2] Ernest W. Lefever and Wynfred Joshua. “UN Peacekeeping in the Congo: 1960-1964: An Analysis of Political, Executive and Military Control.” Brookings Institution. Foreign Policy Studies Division. Arms Control and Disarmament Agency. (1966): pp. Appendix C1-2.

[3] Henning Melber. "Dag Hammarskjöld, the UN and Africa." Review of African Political Economy 39, no. 131 (2012): 152. Accessed December 7, 2020.

[4] Lefever and Joshua, 1966, Appendix B.

[5] Ibid., Appendix K1-2.

[6] A. Walter Dorn, “U THANT: Buddhism in Action,” in The UN Secretary-General and Moral Authority, ed. Kent Kille, (Georgetown University Press: 2007), pp. 149.

[7] Security Council Resolution 169, The Congo Question, [S/5002] (24 November 1961), available from

[8] A. Walter Dorn. “The UN’s First “Air Force”: Peacekeepers in Combat, Congo 1960-1964” The Journal of Military History no. 77 (2013):1399-1425.

[9] Lefever and Joshua, 1966, Appendix H, Chart E