United Nations Issues: Overview of the United Nations System

The United Nations (UN) system comprises interconnected entities including the United Nations, specialized agencies, peacekeeping operations, funds and programs, and other entities. Congress has generally supported the UN system and often uses UN mechanisms to further U.S. foreign policy objectives. At the same time, some Members have been critical of the organization, arguing that UN actions or decisions do not align with U.S. policy priorities, or that UN entities are not operating as effectively as possible. The Trump Administration is in the process of withdrawing the United States from more than 30 UN bodies that it views as contrary to U.S. interests. It has also delayed or halted payments to some UN entities, including the UN regular budget and UN peacekeeping.

UN System Background and Structure

Each entity within the UN system has different mandates, structures, leadership, and funding mechanisms. UN bodies are primarily funded through assessed and voluntary contributions from UN members (or a combination of both). Assessed contributions are required dues, the payment of which is a legal obligation accepted by a country when it becomes a member. Voluntary contributions are provided at the discretion of donors and often finance special funds, programs, and offices. Key parts of the UN system are described below.

The United Nations

Established in the aftermath of World War II, the United Nations is an intergovernmental organization composed of 193 member states. The UN Charter, a treaty to which the United States is a party, is the founding document of the United Nations. Article 1 of the Charter states that the purposes of the organization are to maintain international peace and security; develop friendly relations among nations; solve economic, social, cultural, or humanitarian problems; and promote human rights. The United Nations comprises several key bodies:

• The 193-member UN General Assembly (UNGA) is the organization's primary decisionmaking body. It approves the UN regular and peacekeeping budgets and supports the work of its committees and subsidiary organs, such as the UN Human Rights Council.
• The 15-member UN Security Council (UNSC) is mandated with maintaining international peace and security. It includes 5 permanent members with veto power (United States, China, France, Russia, and the United Kingdom) and 10 nonpermanent members, who are elected by the Assembly for two-year terms.
• The UN Secretariat is the UN administrative body located at UN Headquarters in New York City. It is led by the UN Secretary-General (UNSG), who serves as chief administrative officer. The UNSG is appointed by UNGA on the recommendation of the UNSC. The UNSG serves a five-year term, with the possibility of a second term.

The United Nations also includes the Economic and Social Council, a 54-member UN body that addresses economic, social, and environmental issues, and the International Court of Justice, the principal UN judicial body.

The United Nations is funded through the UN regular budget, which totaled $3.45 billion in 2026. The United States has the largest assessed contribution (22%), followed by China (20%) and Japan (6.9%). UN members approve assessment levels every three years based on a formula taking into account gross national income and other economic data. The United States often accumulates arrears to the regular budget due to differences between the U.S. and UN fiscal years (which affects the timing of U.S. payments), delayed contributions, and U.S. withholdings. The United Nations reports that as of September 30, 2026, U.S. arrears to the UN regular budget totaled $1.31 billion.

UN Specialized Agencies

The UN system has 15 specialized agencies, each of which is a legally independent organization with its own constitution, membership, and assessed budget (Figure 1).

UN Peacekeeping

The United Nations currently operates 11 UN peacekeeping missions worldwide, with more than 44,000 personnel from over 110 countries. The UNSC is responsible for establishing and renewing each operation, as well as determining the mission's mandate. The United States, as a permanent UNSC member, plays a key role in shaping peacekeeping missions. The approved budget for the 2025-2026 peacekeeping fiscal year is $5.4 billion. The United States is generally the largest contributor, assessed 26.15% of the total peacekeeping budget, followed by China (23.78%) and Japan (6.93%). In 1994, Congress enacted a 25% cap on U.S. funding to UN peacekeeping. Over the years, the gap between the U.S. cap and UN assessment has led to the accumulation of U.S. arrears. As of September 30, 2026, U.S. peacekeeping arrears totaled $2.95 billion due to the peacekeeping cap, differences between the U.S. and UN peacekeeping fiscal years, and other U.S. withholdings and delayed payments.

UN Funds and Programs

UN funds and programs are generally established by the UNGA and have a specific mandate. The UNSG appoints the head of each entity, while the governing boards (composed of UN members) review policies and activities. Funds and programs rely on voluntary contributions from governments, the private sector, and civil society. Such contributions might fund the core budgets of these bodies or be earmarked for specific activities. Examples of funds and programs include the UN Children's Fund, UN Development Program, and World Food Program.

Other Entities and Related Organizations

Several other UN entities do not fall under the previous categories, including the UN Office of the High Commissioner for Refugees, UN Women, and UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA). Like UN funds and programs, these bodies focus on specific issues and rely on voluntary funds. Depending on the organization, their heads are appointed by the UNSG or elected by the UNGA. Other separate UN-related bodies, such as the International Atomic Energy Agency and International Organization for Migration, are part of the UN system but not considered UN bodies. They may have special agreements with the UNSC or UNGA.

U.S. Participation in the UN System

The United States played a lead role in the establishment of the United Nations in 1945 and has historically been the largest financial contributor to many UN entities. It is a member of UNGA and is a permanent member of the UNSC. It is also a member of 11 UN specialized agencies and has often been elected to leadership positions on UN boards, councils, and other bodies. U.S. participation in and funding of the United Nations is authorized through the UN Participation Act of 1945 (P.L. 79-264, as amended). Authorization for participation in other UN bodies is also included in the Foreign Assistance Act of 1961 (§301 of P.L. 87-195, as amended), and other legislation.

Both Congress and the executive branch play key roles in furthering U.S. policy toward the UN system. Congress authorizes and appropriates U.S. funding, while the executive branch represents and shapes U.S. policy through the State Department and the U.S. Mission to the United Nations in New York City. The President nominates ambassadors for UN posts, and the Senate provides advice and consent for nominees. This includes the U.S. Permanent Representative, who represents the United States in UN fora. Over the years, both Congress and the executive branch have adjusted or conditioned certain U.S. funding to UN entities. Many have also sought UN reform with a focus on improving management and accountability. Congress oversees the executive branch through UN-related hearings, reporting requirements, and consultations.

U.S. policy toward the UN system has varied during the past two decades. Presidents Obama and Biden supported U.S. participation in and funding of the UN system. The first Trump Administration proposed decreases in UN funding and withheld funds to some UN bodies; however, Congress funded most UN entities at higher levels. During the second Trump Administration, the President proposed eliminating most assessed and all voluntary funding to many UN bodies, including the UN regular budget and UN peacekeeping. Congress rescinded funding to certain UN-related appropriations accounts (P.L. 119-28), while at the same time appropriating funding to other UN entities (Division F of P.L. 119-75). On February 4, 2025, President Trump issued Executive Order 14199, which directed U.S. withdrawal from the UN Human Rights Council, WHO, and UNRWA. It also called for a review of U.S. participation in all international organizations (IOs), including UNESCO (from which the United States withdrew in July 2025). On January 7, 2026, the President instructed U.S. agencies to cease participation in or funding of 66 IOs, including 31 UN entities, that "operate contrary to U.S. national interests, security, economic prosperity, or sovereignty." Such UN entities included the UN Conference on Trade and Development, the UN Democracy Fund, the UN Framework Convention on Climate Change, and UN Women, among others.

Selected Congressional Considerations

UN role and effectiveness. Many policymakers have long debated the effectiveness of UN entities. For example, some express concern that the UNSC has taken insufficient action on certain peace and security issues (such as the Russia-Ukraine and Israel-Hamas conflicts), or that the Human Rights Council does not effectively address human rights violations (while disproportionately focusing on Israel). At the same time, many acknowledge the benefits of the UN system, particularly its convening power, burden-sharing principles, and role in setting global norms and standards.

Influence of other countries. Policymakers may assess the implications of reduced U.S. participation in and funding of the UN system, including the possibility of leaving a leadership vacuum that could increase the influence of other countries relative to the United States. Specifically, many Members have expressed concern with what they view as China's increased role and influence in the UN system.

U.S. funding. Some Members of Congress may consider areas where the United States can leverage its position as one of the largest UN financial contributors to pursue its policy priorities, including UN reform. Members may also examine the impact, if any, of U.S. withholdings on both U.S. influence in UN fora, and/or on UN operations more broadly. Looking ahead, some Members might consider whether to specify funding levels or conditions for specific UN entities in FY2027 funding bills or other legislation.