The United Nations

President Franklin D. Roosevelt and Prime Minister Winston Churchill signed the Atlantic Charter, outlining a vision for a postwar world order based on self-determination, free trade, disarmament, and collective security. The Charter became the foundational document of the Allied war aims and the philosophical basis for the United Nations.

Representatives of 26 Allied nations signed the Declaration by United Nations, pledging to continue fighting the Axis powers and not to make separate peace agreements. The term "United Nations" was coined by President Franklin D. Roosevelt and used for the first time in this document. The declaration was later signed by 21 additional nations.

Delegates from 50 nations signed the Charter of the United Nations at the San Francisco War Memorial and Performing Arts Center. The Charter established the UN's six principal organs: the General Assembly, Security Council, International Court of Justice, Secretariat, Economic and Social Council, and Trusteeship Council. Poland signed later, bringing the original membership to 51.

The UN Charter entered into force after ratification by the five permanent members of the Security Council (China, France, the Soviet Union, the United Kingdom, and the United States) and a majority of other signatories. October 24 is celebrated annually as United Nations Day.

The UN General Assembly adopted the Universal Declaration of Human Rights (UDHR), the first global statement of fundamental human rights to be universally protected. Drafted by a committee chaired by Eleanor Roosevelt, the 30 articles established rights including freedom of speech, assembly, and religion, as well as economic, social, and cultural rights.

The UN Security Council authorized military intervention in Korea after North Korea invaded the South, marking the first major military action by the UN. The Soviet Union was boycotting the Security Council at the time, so could not veto the resolution. A UN force of 16 nations, led by the United States under General Douglas MacArthur, fought to repel the invasion.

The UN General Assembly established the United Nations Emergency Force (UNEF), the first armed peacekeeping force, to supervise the withdrawal of invading forces during the Suez Crisis. UNEF was created through the "Uniting for Peace" resolution, which allowed the General Assembly to act when the Security Council was deadlocked by vetoes.

The UN General Assembly adopted the Declaration on the Granting of Independence to Colonial Countries and Peoples, affirming the right of all peoples to self-determination. The declaration catalyzed the decolonization wave of the 1960s and 1970s, as dozens of African, Asian, and Caribbean nations gained independence and joined the UN as sovereign states.

The UN General Assembly established the United Nations Development Programme (UNDP) by merging the Expanded Programme of Technical Assistance and the UN Special Fund. The UNDP became the UN's primary agency for coordinating development assistance, poverty reduction, and capacity building in developing countries.

Following the UN Conference on the Human Environment (Stockholm Conference), the UN Environment Programme (UNEP) was established to coordinate environmental activities and assist developing countries in implementing environmentally sound policies. UNEP was the first UN agency to be headquartered in the Global South, reflecting the growing importance of developing-country perspectives.

The UN Conference on Environment and Development (Earth Summit) brought together 172 nations, producing the Rio Declaration, Agenda 21, and the UN Framework Convention on Climate Change (UNFCCC). The UNFCCC established the framework for international climate negotiations, leading to the Kyoto Protocol and the Paris Agreement.

The UN General Assembly adopted the Millennium Declaration, establishing eight Millennium Development Goals (MDGs) with measurable targets for reducing poverty, hunger, disease, and inequality by 2015. The MDGs became the most ambitious anti-poverty framework in history, contributing to a halving of global extreme poverty.

The five permanent members of the UN Security Council (the United States, Russia, China, the United Kingdom, and France) each hold veto power over substantive resolutions. Over the decades, the veto has repeatedly blocked action on major conflicts, including the Syrian Civil War (Russia and China vetoed resolutions condemning the Assad regime beginning in 2011), the Russian invasion of Ukraine (Russia vetoed condemnation in 2022), and Israeli-Palestinian conflicts (the US has vetoed dozens of resolutions critical of Israel). Critics argue that the veto system paralyzes the Security Council on precisely the conflicts where its permanent members are involved or have strategic interests, undermining the UN's core mandate to maintain international peace. Defenders of the system argue that the veto reflects geopolitical reality and that requiring great-power consensus prevents the Security Council from becoming an instrument of any single power bloc. Reform proposals, including expanding permanent membership to include India, Brazil, Germany, and African nations, have been debated for decades without success.

The UN General Assembly adopted the 2030 Agenda for Sustainable Development, establishing 17 Sustainable Development Goals (SDGs) to replace the MDGs. Later that year, the Paris Agreement on climate change was adopted by 196 parties at COP21. The SDGs and Paris Agreement represented the most comprehensive global framework for addressing poverty, inequality, and climate change.