The United States is a charter member of the United Nations and one of five permanent members of the UN Security Council.

The United States boasts the headquarters of the United Nations, which includes the usual meeting place of the General Assembly in New York City, on the northeast coast of the country. The United States is the largest provider of financial contributions to the United Nations, providing 27.89 percent of the UN assessed peacekeeping budget of $6.38 billion for fiscal year 2020 (China and Japan contributed 15.2 percent and 8.5 percent, respectively). The assessed peacekeeping budget is separate from voluntary contributions and the assessed regular budget. The assessed regular budget of the UN for fiscal year 2022 in $3.12 billion. From July 2016 to June 2017, 28.6 percent of the budget used for peacekeeping operations was provided by the United States. The United States had a pivotal role in establishing the UN.

Role in establishing the UN The UN is an outgrowth of the Atlantic Charter. It appeared in the Declaration by United Nations on January 1, 1942, in which 26 nations pledged to continue fighting the Axis powers.

Their main inspiration was the League of Nations; however, their goals were to rectify the League's imperfectionsJohn Allphin Moore and Jr. Jerry Pubantz. The New United Nations: International Organization in the Twenty-First Century (Upper Saddle River, New Jersey : Pearson Prentice Hall, 2006), 43-44 in order to create an organization that would be "the primary vehicle for maintaining peace and stability."John Allphin Moore and Jr. Jerry Pubantz. The New United Nations: International Organization in the Twenty-First Century (Upper Saddle River, New Jersey : Pearson Prentice Hall, 2006), 44 Roosevelt's main role was to convince the different allies, especially Winston Churchill of the United Kingdom and Joseph Stalin of the Soviet Union, to join the new organization. The negotiations mainly took place during the Dumbarton Oaks Conference and the Yalta Conference, where the three world leaders tried to reach a consensus concerning the United Nations' structure, purposes and principles.John Allphin Moore and Jr. Jerry Pubantz. The New United Nations: International Organization in the Twenty-Fifth Century (Upper Saddle River, New Jersey : Pearson Prentice Hall, 2006), 43 "Roosevelt saw the United Nations as the crowning achievement of his political career."John Allphin Moore and Jr. Jerry Pubantz. The New United Nations: International Organization in the Twenty-First Century (Upper Saddle River, New Jersey : Pearson Prentice Hall, 2006), 46 Roosevelt's envoy Wendell Willkie played a key role in promoting the idea of the United States joining the new organization, publishing One World in April 1943. In September 1943, 81 percent of Americans—up from 63 percent in February—supported joining a "union of nations" after the war.

In 1945, representatives from 50 countries met in San Francisco for the United Nations Conference on International Organization. They deliberated on proposals that had been drafted by representatives of the Republic of China, the Soviet Union, the United Kingdom and the United States at the Dumbarton Oaks Conference between August and October 1944. Roosevelt, Churchill and Stalin reviewed the Dumbarton Oaks proposal during the Yalta Conference in February 1945. The purpose of the conference was to discuss post-war settlementsJohn Allphin Moore and Jr. Jerry Pubantz. The New United Nations: International Organization in the Twenty-First Century (Upper Saddle River, New Jersey : Pearson Prentice Hall, 2006), 51 and to reach a final agreement concerning "the UN's structure and membership and set the date of the San Francisco organizing conference."John Allphin Moore and Jr. Jerry Pubantz. The New United Nations: International Organization in the Twenty-First Century (Upper Saddle River, New Jersey : Pearson Prentice Hall, 2006), 52 The world leaders eventually agreed on Roosevelt's proposal to give certain members a veto powerFrancis O. Wilcox. “II. The Yalta Voting Formula” The American Political Science Review 39, no. 5 (Oct, 1945), 953 so "that the Organization could take no important action without their joint consent."Francis O. Wilcox. “II. The Yalta Voting Formula” The American Political Science Review 39, no. 5 (Oct, 1945), 944 Though the veto power question created a lot of disagreement among the different signatories,Francis O. Wilcox. “II. The Yalta Voting Formula” The American Political Science Review 39, no. 5 (Oct, 1945), 943 its inclusion in the charter was never a matter of negotiation for Roosevelt and his allies.Francis O. Wilcox. “II. The Yalta Voting Formula” The American Political Science Review 39, no. 5 (Oct, 1945), 954 Finally, during the Yalta conference, Stalin agreed to make the USSR a member of the United Nations.

An important American contribution, prior to the formation of the United Nations, was made at the Bretton Woods Conference. This conference took place in 1944 and its goal was "to create a new international monetary and trade regime that was stable and predictable."John Allphin Moore and Jr. Jerry Pubantz. The New United Nations: International Organization in the Twenty-First Century (Upper Saddle River, New Jersey : Pearson Prentice Hall, 2006), 53 Over subsequent decades, this new system opened world markets and promoted a liberal economy. It was implemented through different institutions, such as the World Bank and the International Monetary Fund, which went on to work with the United Nations but remained independent from it.Chronis Polychroniou. “Rise and Fall of US Imperialism” Economic and Political Weekly 30, no. 30 (July 29, 1995), 58

On July 28, 1945, the United States Senate (as part of the 79th United States Congress) ratified the United Nations Charter by a vote of .Carroll, Mitchell B. “Further Action on United Nations Charter.” American Bar Association Journal, vol. 31, no. 9, 1945, pp. 457–58. JSTOR, http://www.jstor.org/stable/25715332. Accessed 4 July 2024.Gillette, Guy M., et al. “UNITED NATIONS CHARTER REVIEW.” Proceedings of the American Society of International Law at Its Annual Meeting (1921-1969), vol. 48, 1954, pp. 191–211. JSTOR, http://www.jstor.org/stable/25657319. Accessed 4 July 2024. (By comparison, the Senate had voted in favor of joining the League of Nations, short of the required two-thirds majority for ratification.) The United Nations officially came into existence on October 24, 1945, when all of the Permanent Five (the Republic of China, France, the Soviet Union, the United Kingdom, and the United States) as well as a majority of other signatories had ratified the Charter.

The United Nations was the first international governmental organization to receive significant support from the United States. Its forerunner, the League of Nations, had been championed by Woodrow Wilson after World War I to prevent future conflicts. While it was supported by most nations of Europe, it was never ratified by the United States Congress due to the inability to reach a compromise regarding the Lodge Reservations or the Hitchcock Reservations.

Shortly after the establishment of the United Nations, the United States came into conflict with another member of the Security Council. Since the Soviet Union was a permanent member of the United Nations Security Council, it had the power to veto any binding UN resolution. In fact, Soviet foreign minister and UN ambassador Vyacheslav Molotov used veto power twice as often as any other permanent member, earning him the title "Mr. Veto".

Relations between the United States and the Soviet Union (later Russia) within the UN have evolved in step with the larger geopolitical situation between the two powers. While the Soviet Union was boycotting the Security Council and China's seat was represented by U.S.-friendly Republic of China (instead of the communist People's Republic of China which would replace the ROC in the UN in 1971), the U.S. and UN jointly condemned the invasion of South Korea by North Korean troops, leading to the UN sanctioned Korean War. Later, the U.S. persuaded all permanent members of the Security Council to authorize force against Ba'athist Iraq in the Gulf War of 1991. This was a major step toward U.S. and Russian reconciliation in the post–Cold War era.

Sources of conflict Since 1991, the United States has been the world's dominant military, economic, social, and political power (not to mention hosting the UN Headquarters itself in New York City); the United Nations was not designed for such a unipolar world with a single superpower, and conflicts between an ascendant U.S. and other UN members have increased. China question

Conflict between the U.S. and the UN predates the collapse of the Soviet Union. In 1971, the UN adopted Resolution 2758—which affected the admission of the People's Republic of China and the removal of the Republic of China—despite objections by the U.S. government (see China and the United Nations). The U.S. government changed its own China policy shortly afterward, however, so the conflict between the UN and US foreign policy was short-lived.Eugene J. Alpert, and Samuel J. Bernstein, "International bargaining and political coalitions: US foreign aid and China's admission to the UN." Western Political Quarterly 27.2 (1974): 314-327. online

Israeli–Palestinian conflict

The U.S. government's repeated opposition to Arab military actions has created much more tension between the U.S. government and the United Nations. The General Assembly Resolution 3379 (determining that Zionism is a form of racism and racial discrimination) of 1975 was strongly opposed by U.S. officials. In 1991, the General Assembly adopted Resolution 4686, which effectively negated Resolution 3379. Use of its veto power to prevent the Security Council from issuing resolutions condemning Israel Defense Forces action has frequently divided the U.S. from the Soviet Union, China and France in the Security Council; since 1989, the U.S. government has dissented against Security Council resolutions on 12 occasions out of 17 total instances when a permanent member vetoed. Of these 12 occasions, only two related to issues other than the Israeli–Palestinian conflict. In 2009, the U.S. government abstained from Security Council Resolution 1860, which called for a halt to Israel's military response to Hamas rocket attacks, and the opening of the border crossings into the Gaza Strip. Christian Henderson, and Noam Lubell, "The contemporary legal nature of UN Security Council ceasefire resolutions." Leiden Journal of International Law 26.2 (2013): 369-397.

Dues

Under the Reagan administration, the U.S. withdrew from UNESCO, and withheld its dues to encourage the UN to repeal Resolution 3379, which it did in 1991. The U.S. was—and continues to be—the member state levied most heavily by the UN, so U.S. policymakers expected this strategy to be an effective way to oppose Soviet and Arab influence over the UN. When the UN repealed Resolution 3379, the U.S. resumed dues payments, but not before the U.S. had accumulated significant and controversial arrears. Robert S. Jordan, "Boycott diplomacy: the US, the UN, and UNESCO." Public Administration Review 44.4 (1984): 283-291.

Vetoing second term of the Secretary-General