What is the United Nations? What the UN does and can't do

The United Nations is an international organization of 193 member countries, founded in 1945 after World War II to prevent another war and help countries work together. Every member has a seat in its General Assembly, while a 15-member Security Council can make decisions that bind all of them. Through agencies such as the World Health Organization and UNICEF, it also delivers aid, coordinates health and sets global standards. It is not a world government: it has only the powers its members give it.

In short

• The UN is a forum and a toolbox: 193 countries meet, argue and sometimes act together, through bodies with very different powers.
• Only the Security Council can make binding decisions, and any of its five permanent members can veto them.
• Much of what the UN does day to day is aid, health, refugees and peacekeeping, run through its agencies and missions.

Why was the UN created?

The UN was the second attempt at a world peace organization. The first, the League of Nations, founded after World War I, failed to stop the aggression that led to World War II, in part because the United States never joined and the League had no means to enforce its decisions. During the war, the Allies began calling themselves the "United Nations", and in 1945 they built a new organization around that name.

Representatives of 50 countries drafted the UN Charter in San Francisco between April and June 1945 and signed it on 26 June, according to the UN's history. It came into force on 24 October 1945, now marked as United Nations Day, once China, France, the Soviet Union, the United Kingdom, the United States and a majority of the other signatories had ratified it. Membership grew as colonies became independent states; South Sudan, in 2011, was the 193rd.

The Charter sets out the UN's purposes: to maintain international peace and security, to develop friendly relations based on equal rights and self-determination, to cooperate on economic, social and humanitarian problems and on human rights, and to be a center where countries coordinate. It also bans the threat or use of force against another state's territory, with exceptions for self-defense and for action the Security Council authorizes.

What are the UN's main parts?

The Charter created six main organs, listed on the UN's own site, plus a family of agencies and programs.

Body	Who is in it	What it can do
General Assembly	All 193 members, one vote each	Debates any issue, approves the budget, elects members of other bodies; its resolutions are recommendations, not law
Security Council	15 members: 5 permanent (China, France, Russia, the UK, the US) and 10 elected for two years	Decides on threats to peace; can impose sanctions or authorize force; its decisions bind every member
Secretariat	International staff led by the Secretary-General	Runs the UN day to day; the Secretary-General can bring threats to the Council's attention
Economic and Social Council	54 members elected by the Assembly	Coordinates economic, social and environmental work
International Court of Justice	15 judges, in The Hague	Settles legal disputes between states that accept its jurisdiction; gives advisory opinions
Trusteeship Council	The five permanent members	Supervised territories on the way to independence; inactive since 1994, its job done

Around them sit specialized agencies and funds with their own budgets and governing boards: the World Health Organization, UNICEF for children, the World Food Programme, the UN refugee agency UNHCR, and many more. The Secretary-General is appointed by the General Assembly on the Security Council's recommendation, for five-year terms. António Guterres has held the post since 1 January 2017, and his second term runs to 31 December 2026.

How does the Security Council's veto work?

A decision on anything beyond procedure needs at least 9 of the 15 votes in favor and no vote against from any of the five permanent members. That "no" from a permanent member is the veto. By long practice, a permanent member that abstains does not block a decision. The arithmetic shows why the veto is so powerful.

Votes on a draft resolution	Result
14 yes, 1 no from a permanent member	Fails: vetoed
9 yes, 6 no, none of them permanent members	Passes
8 yes, 7 abstentions	Fails: fewer than 9 yes votes
12 yes, 3 abstentions, including two permanent members	Passes: abstaining is not a veto

The veto means the Security Council can act only when the five permanent members do not oppose it, which is why the UN is weakest in exactly the conflicts in which a permanent member or its ally is involved. Every permanent member has used it, the Soviet Union and Russia most often, followed by the United States. On 26 April 2022, the General Assembly adopted resolution 76/262, a standing mandate to meet within 10 working days after any veto so that the vetoing country can explain itself. It added scrutiny, not power.

The veto was deliberate. The founders believed that the UN would collapse, as the League had, unless the great powers had a reason to stay in it, and they accepted that it could not act against any of them.

What does the UN actually do?

Most of the UN's work never reaches the Security Council.

• Peacekeeping. Lightly armed troops and police from member states, in blue helmets, monitor ceasefires and protect civilians with the consent of the countries involved. The UN listed 11 peacekeeping operations in September 2026, from Cyprus and Lebanon to South Sudan. UN peacekeepers received the Nobel Peace Prize in 1988.
• Humanitarian aid. The World Food Programme, which won the Nobel Peace Prize in 2020, UNICEF and UNHCR feed, shelter and vaccinate people in wars and disasters.
• Health. The World Health Organization coordinated the campaign that eradicated smallpox, declared in 1980, and sets international health rules.
• Rules and standards. UN bodies set shared rules for aviation, shipping, telecommunications and the postal system, which most people never notice because they work.
• Rights and development. The General Assembly adopted the Universal Declaration of Human Rights in 1948 and, in 2015, the 17 Sustainable Development Goals for 2030.

What can't the UN do?

The UN has no army of its own, no power to tax, and no authority over a country's internal affairs unless the Security Council acts under Chapter VII of the Charter. Peacekeepers are lent by members and can be withdrawn. The budget depends on members paying their assessed contributions, and when large contributors pay late or cut back, programs shrink. In March 2025 the Secretary-General launched a review called UN80 to cut costs and merge overlapping work.

Still argued

The most persistent argument is about reforming the Security Council. Its permanent seats reflect the winners of 1945, so India, Brazil, Germany, Japan and the countries of Africa press for permanent seats or a larger council. Supporters of the current design argue that a council the great powers trust is more useful than a larger one they ignore. Reform is hard to achieve: changing the Charter needs two-thirds of the General Assembly and ratification by two-thirds of members, including all five permanent members, so any one of them can block it. A wider debate asks whether the UN keeps peace at all. Its defenders point to wars avoided and aid delivered; its critics point to Rwanda in 1994 and Srebrenica in 1995, where peacekeepers failed to stop mass killings.

The UN is often confused with other groups. NATO is a military alliance of 32 members, not a universal body. The European Union makes laws that bind its members directly, which the UN General Assembly cannot. And the G7 is an informal club of seven large economies with no charter at all. The UN admits democracies and autocracies alike, which is both its reach and its limit.

Check yourself

• Without looking back: what can the Security Council do that the General Assembly can't?
• Why did the UN's founders give five countries a veto, knowing it would paralyze the Council at times?
• Name three things the UN does that have nothing to do with the Security Council.

Sources

• United Nations Charter, full text — United Nations, 1945
• History of the United Nations — United Nations
• Main bodies — United Nations
• Peacekeeping data — United Nations Peacekeeping, 2026
• Resolutions of the 76th session of the General Assembly — United Nations, 2022