On September 28, 2012, President Barack Obama signed H.J.Res. 117 , "making continuing appropriations for fiscal year 2013" ( P.L. 112-175 ), which extended through March 27, 2013, spending levels "at a rate for operations as provided in the applicable appropriations Acts for fiscal year 2012 and under the authority and conditions provided in such Acts." On February 13, 2012, the President had transmitted the FY2013 budget to Congress. The request included $1,570,005,000 for the Contributions to International Organizations (CIO) account, Department of State, including $1,151,478,000 for U.S. assessed contributions to United Nations (U.N.) system budgets; $2,098,500,000 for the Contributions to International Peacekeeping Activities (CIPA) account, Department of State; and $327,300,000 for the International Organizations and Programs (IO&P) account, Foreign Operations, which includes voluntary contributions to several U.N. system programs. The President requested, through the Nonproliferation, Anti-terrorism, Demining, and Related Programs (NADR) account, Foreign Operations, $90,900,000 for U.S. voluntary contributions to the International Atomic Energy Agency (IAEA). This account also includes a request for $1,350,000 in U.S. voluntary contributions to the U.N. Security Council Resolution 1540 [(2004)] Trust Fund. The United States has been, and remains, the single largest financial contributor to the United Nations (U.N.) system. For calendar year (CY) 2007, U.S. contributions to the U.N. system totaled just over $4.8 billion. This included more than $895,982,000 in assessed contributions to the regular budgets of the United Nations and its specialized agencies; $96,414,194 in assessed contributions to the two war crimes tribunals; $1,266,129,767 in assessed contributions to U.N. peacekeeping operations; and $2,560,429,000 in voluntary contributions to U.N. system special programs and funds. In recent years, however, Congress has been pressing to reduce U.S. funding for many U.N. system programs. Congressional debate over U.N. funding has focused on several questions: (1) What is the appropriate level of U.S. funding for U.N. system operations and programs? (2) What U.S. funding actions are most likely to produce a positive continuation of U.N. system reform efforts? and (3) What is the status of U.S. accumulated arrearages? This report tracks the process by which Congress provides the funding for U.S. assessed contributions to the regular budgets of the United Nations, its agencies, and U.N. peacekeeping operation accounts as well for U.S. voluntary contributions to U.N. system programs and funds. It includes information on the President's request and the congressional response as well as congressional initiatives during this legislative process. Basic information is provided to help the reader understand this process. The United Nations (U.N.) system is made up of variously interconnected components including specialized agencies, voluntary funds and programs, peacekeeping operations, and the U.N. organization itself. The system is financed by contributions from member and/or participant states. The contributions are usually made in two ways: assessed contributions—required "dues" at percentages established by the membership of each organization involved—and voluntary contributions, which represent more than half of the total aggregated funds received by the U.N. system. Assessed contributions finance the regular budgets of the United Nations, the specialized agencies, and the International Atomic Energy Agency (IAEA). Payment of the assessed contribution is one of the legal obligations accepted by a country when it joins the organization. In this way, the organization has a regular source of income for staffing and implementation of authorized programs. Most U.N. peacekeeping operations are funded through special assessed accounts created by the U.N. General Assembly. U.S. assessed contributions are funded from the State Department's budget. Congress authorizes these funds as part of the Foreign Relations Authorization Act and currently appropriates the money in the Department of State, Foreign Operations, and Related Programs appropriations legislation. The regular assessed budgets of U.N. system organizations as well as regional and other non-U.N. intergovernmental organizations are included in the Contributions to International Organizations (CIO) account, while assessed peacekeeping contributions are funded in the Contributions to International Peacekeeping Activities (CIPA) account. Voluntary contributions finance special programs and offices created by the U.N. system, such as the United Nations Development Program (UNDP), the United Nations Environment Program (UNEP), the United Nations Children's Fund (UNICEF), and the U.N. Democracy Fund (UNDEF). Payment of these contributions is entirely up to each individual country; no country is legally obliged to contribute to these programs. U.S. voluntary contributions are financed through the foreign assistance authorization and appropriation legislation, primarily through the International Organizations and Programs (IO&P) account of what was formerly the Foreign Operations Act. This IO&P account does not fund U.S. voluntary contributions to the U.N. High Commissioner for Refugees (UNHCR) and the U.N. Relief and Works Agency for Refugees in the Near East (UNRWA), which are funded through the Migration and Refugee Assistance (MRA) account, International Atomic Energy Agency (IAEA), which is funded through the Nonproliferation, Anti-terrorism, Demining, and Related Programs (NADR) account, Foreign Operations, or World Food Program. On February 13, 2012, President Barack Obama transmitted the FY2013 budget to Congress. The request included $1,570,005,000 for the Contributions to International Organizations (CIO) account, Department of State, including $1,151,478,000 for U.S. assessed contributions to United Nations (U.N.) system budgets; $2,098,500,000 for the Contributions to International Peacekeeping Activities (CIPA) account, Department of State; $327,300,000 for the International Organizations and Programs (IO&P) account, Foreign Operations, which includes voluntary contributions to several U.N. system programs; and $90,900,000 for U.S. voluntary contributions to the International Atomic Energy Agency (IAEA), through the Nonproliferation, Anti-terrorism, Demining, and Related Programs (NADR) account, Foreign Operations. This account also includes a request for $1,350,000 in U.S. voluntary contributions to the U.N. Security Council Resolution 1540 [(2004)] Trust Fund. On May 24, 2012, the Senate Appropriations Committee reported S. 3241 , the Department of State, Foreign Operations, and Related Programs Appropriations Act, 2013. The committee recommended $1,389,737,000 for the CIO account, with no funding for assessed contributions to UNESCO; $2,006,500,000 for the CIPA account, without $142,100,000 for assessed peacekeeping in Somalia which was moved to the PKO account; and $375,000,000 for the IO&P account, with a table breaking out the specific committee recommendations for each program. The OCO account included $101,300,000 for the CIO account for U.N. support to Afghanistan and Iraq. On May 25, 2012, the House Appropriations Committee reported H.R. 5857 , the Department of State, Foreign Operations, and Related Programs Appropriations Bill, 2013. The committee recommended $1,310,769,000 for the CIO account, with no funding for U.S. assessed contributions for UNESCO; $1,828,182,000 for the CIPA account, moving funding (an unspecified amount) for assessed contributions to the U.N. logistics and support package for the AU Mission in Somalia to the PKO account; and $276,500,000 for the IO&P account, including $131,755,000 for UNICEF but no funds for U.S. voluntary contributions to UNFPA, the IPCC/UNFCCC, and to UNESCO. Language requested to increase the peacekeeping assessment cap from 25% to 27.2% was not included. Title VIII, the OCO account, included $101,300,000 for the CIO account for support of contingency operations in Afghanistan and Iraq (UNAMA and UNAMI). This had not been included in the OCO request. On September 28, 2012, the President signed H.J.Res. 117 , "making continuing appropriations for fiscal year 2013" ( P.L. 112-175 ), which extended through March 27, 2013, funding for FY2013 at a rate for operations as provided in the applicable appropriations acts for FY2012. On February 13, 2012, President Obama requested $1,570,400,000 for payment of U.S. assessed contributions (CIO account) to the 43 international (including regional) intergovernmental organizations to which the United States belongs. The CIO account request included the following amounts for the United Nations: United Nations regular budget: $567,931,000; U.N. Capital Master Plan (CMP): $0; U.N. War Crimes Tribunal—Yugoslavia: $16,354,000; and U.N. War Crimes Tribunal—Rwanda: $11,949,000. The aggregated total for this category is $596,234,000.