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 it is not operating as effectively as possible. Most recently, the second Trump Administration called for a review of U.S. participation in and funding of all international organizations (IOs), including UN bodies. It also proposed pausing most assessed and all voluntary contributions to the United Nations and other IOs in its FY2026 budget request.
UN entities have different mandates, structures, leadership, and funding mechanisms. Each body is 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 finance special funds, programs, and offices.
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. Key parts of the UN system include the following:
- The 193-member 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 (HRC).
- The 15-member 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 Secretariat is the UN administrative body located at UN Headquarters in New York City. It is led by the Secretary-General (UNSG), who serves as chief administrative officer. The SG is appointed by UNGA on the recommendation of the SC. The UNSG serves a five-year term, with the possibility for a second term.
The UN system also includes the UN Economic and Social Council, a 54-member body that addresses economic, social, and environmental issues, and the International Court of Justice, the principal UN judicial body. (For more information, see CRS Report R47715, The United Nations System: Frequently Asked Questions.)
The United Nations is funded through the UN regular budget ($3.72 billion for UN FY2025). The United States' assessed contribution is 22% of the regular budget (an estimated $707.05 million in U.S. FY2024). Other top contributors include 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) and U.S. withholdings from UN activities.
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). Many follow the assessments for the UN regular budget, while others use their own formulas. The United States is a member of all specialized agencies except for UNIDO and UNWTO. In January 2025, President Trump announced the United States would begin the one-year process of withdrawing from WHO.
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Source: United Nations, adapted by CRS. |
UN Peacekeeping
The United Nations currently operates 11 UN peacekeeping missions worldwide, with more than 68,000 personnel from over 120 countries. The UNSC is responsible for establishing and renewing each operation, as well as determining the mission's mandate and budget. The United States, as a permanent UNSC member, plays a key role in shaping peacekeeping missions. The approved budget for the 2024-2025 peacekeeping fiscal year is $5.9 billion. The United States is the largest financial 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 more than $1 billion in arrears. For FY2025, Congress appropriated $1.23 billion for UN peacekeeping, up to the 25% cap.
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 Development Program, UN Environment 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. Like UN funds and programs, these bodies often focus on specific issues and rely on voluntary funding. Depending on the organization, their heads are appointed by the UNSG or elected by the General Assembly. Other separate UN-related bodies such 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 is 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 13 UN specialized agencies and is often 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 (ยง301 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 (USUN) 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 Administrations have adjusted or conditioned 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 and reporting requirements and consultations.
During the past decade, U.S. policy toward the United Nations has varied. The first Trump Administration proposed decreases in UN funding and withheld contributions to some UN bodies; however, Congress funded most UN entities at levels higher than the Administration's requests. The Biden Administration generally supported U.S. engagement in and funding of the UN system. The second Trump Administration issued Executive Order (E.O.) 14199, which called for a review of all IOs of which the United States is a member and/or funds to determine which entities are "contrary to the interests of the United States and whether they can be reformed." The Administration's FY2026 "skinny" budget request would pause most assessed and all voluntary contributions to the United Nations and other IOs. The request states that the President may choose to fund some IOs from a new "America First Opportunity (A1OF) Fund" account.
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 HRC 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 inconsistent or reduced U.S. participation in and funding of the UN system, including the possible increase in influence within the UN of other countries relative to the United States. In particular, many Members have expressed concern with what they perceived to be China's efforts to increase its influence in the UN system.
U.S. Funding and Reform. Members may consider the benefits and drawbacks of U.S. funding to the UN system, including areas where the United States can use funding to increase efficiency and accountability through reform. Some policymakers may also take into account the impact, if any, of U.S. arrears, "pauses," or other withholdings on U.S. influence in UN fora and/or UN operations more broadly. Looking ahead, Congress may consider the outcome of the Administration's review under E.O. 14199 and the extent to which, if any, Members might specify funding levels, conditions, or withholdings for specific UN entities in future authorization and/or appropriations bills.