The UN Security Council

The UN Security Council

The UN Security Council is the premier global body for maintaining international peace and security, but it faces steady calls for reform to better meet twenty-first-century challenges.
Ukrainian President Volodymyr Zelenskyy addresses the Security Council via video amid Russia’s war.
Ukrainian President Volodymyr Zelenskyy addresses the Security Council via video amid Russia’s war. Andrew Kelly/Reuters
  • The fifteen-member UN Security Council seeks to address threats to international security. Its five permanent members, chosen in the wake of World War II, have veto power. 
  • The Security Council fosters negotiations, imposes sanctions, and authorizes the use of force, including the deployment of peacekeeping missions.
  • Critics say the Security Council fails to represent many regions of the world and that increasing frequency of the veto is inhibiting its functionality.


The Security Council, the United Nations’ principal crisis-management body, is empowered to impose binding obligations on the 193 UN member states to maintain peace. The Security Council’s five permanent and ten elected members meet regularly to assess threats to international security, including civil wars, natural disasters, arms proliferation, and terrorism.

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Structurally, the Security Council remains largely unchanged since its founding in 1946, stirring debate among members about the need for reforms. In recent years, members’ competing interests have often stymied the Security Council’s ability to respond to major global conflicts and crises, including the COVID-19 pandemic, Russia’s annexation of Crimea and subsequent invasion of Ukraine, and the war between Israel and Palestinian militant group Hamas. 

What is the Security Council’s structure?

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The Security Council has five permanent members—the United States, China, France, Russia, and the United Kingdom—collectively known as the P5. Any one of them can veto a resolution. The Security Council’s ten elected members, which serve two-year, nonconsecutive terms, are not afforded veto power. The P5’s privileged status has its roots in the United Nations’ founding in the aftermath of World War II. The United States and the Union of Soviet Socialist Republics (USSR) were the outright victors of the war, and, along with the United Kingdom, shaped the postwar political order. As their plans for what would become the United Nations took shape, U.S. President Franklin D. Roosevelt insisted on the inclusion of the Republic of China (Taiwan), envisioning international security presided over by “four policemen.” British Prime Minister Winston Churchill saw in France a European buffer against potential German or Soviet aggression and so sponsored its bid for restored great-power status.

The members of the P5 have exercised the veto power to varying degrees. Counting the years when the Soviet Union held its seat, Russia has been the most frequent user of the veto, blocking 155 resolutions since the Security Council’s founding. Comparatively, the United States has used the veto ninety times; it last vetoed a resolution on December 8, 2023, which called for a cease-fire in the war between Israel and Hamas but did not include language condemning Hamas for its attacks. The United States has historically used its veto power to protect Israel from Security Council decisions, with approximately one-third of its negative votes since 1972 applied to resolutions critical of Israel. China has used the veto more frequently in recent years, though it has historically been more sparing than the United States or Russia; Beijing has now blocked twenty resolutions. Since the dissolution of the USSR in 1991, China and Russia have vetoed together more than a quarter of the time. In contrast, France and the United Kingdom have not exercised their veto power since 1989 and have advocated for other P5 members to use it less.

The Security Council’s presidency rotates o­­­­n a monthly basis, ensuring some agenda-setting influence for its ten nonpermanent members, which are elected by a two-thirds vote of the UN General Assembly. The main criterion for eligibility is contribution “to the maintenance of international peace and security,” often defined by financial or troop contributions to peacekeeping operations or leadership on matters of regional security likely to appear before the Security Council.

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A secondary consideration, “equitable geographical distribution,” gave rise to the regional groups used since 1965 in elections: the African Group has three seats; the Asia-Pacific Group, two; the Eastern European Group, one; the Latin American and Caribbean Group, two; and the Western European and Others Groups (WEOG), two. Each has its own electoral norms. An Arab seat alternates between the African and Asian blocs by informal agreement. Turkey and Israel, which has never served on the Security Council, caucus with WEOG.

Subsidiary organs that support the Security Council’s mission include ad hoc committees on sanctions, counterterrorism, and nuclear, biological, and chemical weapons, as well as the international criminal tribunals for Rwanda and the former Yugoslavia. Within the UN Secretariat, the Department of Peacekeeping Operations and the Department of Operational Support manage field operations. The Peacebuilding Commission, established in 2005 as a repository of institutional memory and best practices, serves an advisory role.

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What are its tools for conflict management?

The Security Council aims to peacefully resolve international disputes in accordance with Chapter VI of the UN Charter, which authorizes the Security Council to call on parties to seek solutions via negotiation, arbitration, or other peaceful means. Failing that, Chapter VII empowers the Security Council to take more assertive actions, such as imposing sanctions or authorizing the use of force “to maintain or restore international peace and security.” Peacekeeping missions are the most visible face of the United Nations’ conflict-management work; as of early 2024, the Security Council oversees eleven operations across three continents, involving a total of nearly ninety-seven thousand uniformed personnel.

Constrained by U.S.-Soviet rivalry, the Security Council acted infrequently in the four-and-a-half decades between its founding and the close of the Cold War. During that time, it authorized seventeen peacekeeping operations [PDF]. Since Russia’s invasion and annexation of Crimea in 2014, tensions have flared between Russia and the Western members of the P5, leading to concerns that the body is less able to defuse crises. Only two peacekeeping missions, in the Central African Republic and Haiti, have been authorized since 2014. The Syrian conflict has proven to be particularly difficult to manage, given that Russia—sometimes joined by China—has used its veto power nearly twenty times to block resolutions aimed at holding the Bashar al-Assad regime accountable for atrocities documented by UN sources. Relations worsened further after Russia invaded Ukraine in 2022, and Moscow has since used its veto power to prevent several Security Council resolutions condemning the conflict. 

The Security Council has authorized sixty peacekeeping operations in the years since the dissolution of the Soviet Union in 1991, many responding to failing states, civil wars, or complex humanitarian emergencies and deploying to conflict zones in the absence of cease-fires or parties’ consent. Under more muscular mandates, they have combined military operations—including less restrictive rules of engagement that allow for civilian and refugee protection—with civilian tasks such as policing, electoral assistance, and legal administration. Developing nations, particularly those in South Asia, provide the lion’s share of personnel.

Regional organizations have played an increasingly important role in peacekeeping and conflict resolution, in some cases prodding the Security Council to act and in others acting as subcontractors on its behalf. For instance, the Security Council authorized the use of force in Libya in 2011 after the Arab League called for a no-fly zone, which the North Atlantic Treaty Organization (NATO) then executed. Experts point to the increased will and capacity of the African Union, which has partnered with the United Nations in carrying out missions in Somalia and Sudan’s Darfur region.

Amid the COVID-19 pandemic in 2020, the Security Council passed Resolution 2532 [PDF], which called for a ninety-day “humanitarian pause” in armed conflicts worldwide, with an exception for conflicts against designated terrorist groups. However, the resolution’s effect was minimal, with just one conflict party—Colombia’s National Liberation Army (ELN)—explicitly citing it in an offer to end hostilities.

What sanctions measures are available to the Security Council?

The sanctions provisions in Article 41 of the UN Charter, dormant during much of the Cold War, have become one of the Security Council’s most frequently employed tools. The body had imposed sanctions just twice prior to the fall of the Berlin Wall: in 1966, a trade embargo was enacted against Southern Rhodesia (now Zimbabwe), and in 1977, an arms embargo was enacted against apartheid-era South Africa. The Security Council began to make regular use of sanctions in the early 1990s, starting with Iraq, the former Yugoslavia, and Haiti. There are currently fifteen Security Council sanctions regimes, listing more than one thousand individuals and entities, in place.

So-called “smart” sanctions emerged in the mid-1990s as an alternative to what then UN Secretary-General Kofi Annan called the “blunt instrument” employed in Iraq following the Gulf War. These sanctions target discrete economic and political matters and specific individuals deemed threats to international security. Arms embargoes, travel bans, asset freezes, and import/export bans on individual goods, rather than comprehensive embargoes, are now the norm.

But targeted sanctions have raised human rights concerns of their own. To be delisted, blacklisted individuals, entities, and items—often those with dual uses, such as agricultural or medicinal applications—require an affirmative vote of sanctions committees, in which all Security Council members are represented.

What role does it play in authorizing military force?

Under the UN charter, members can only use force in self-defense or when they have obtained authorization from the Security Council. However, members and coalitions of countries have often used military force outside of these contexts.

NATO’s seventy-eight-day air war in Kosovo is the most-cited case in arguing for the legitimacy of humanitarian interventions that lack Security Council authorization. After Russia indicated it would block authorization in the Security Council, NATO forces undertook a bombing campaign to protect Kosovar Albanians from ethnic cleansing by Serbs in rump Yugoslavia. An independent commission of scholars later deemed the intervention “illegal but legitimate.”

The emergence of the Responsibility to Protect (R2P) doctrine in the early 2000s appeared to justify the use of force outside Security Council authorization by qualifying the principle of noninterference in sovereign affairs. R2P, as adopted by the UN General Assembly in 2005, stipulates that states have a responsibility to protect their populations from crimes against humanity; the “international community” has a responsibility to use peaceful means to protect threatened populations; and when a state “manifestly fails” to uphold its responsibilities, coercive measures should be collectively taken.

Successive U.S. administrations have argued that humanitarian intervention can be legitimate with the backing of regional organizations or “coalitions of the willing.” But UN Secretary-General Ban Ki-moon rejected this position in 2008, saying, “The responsibility to protect does not alter, indeed it reinforces, the legal obligations of Member States to refrain from the use of force except in conformity with the Charter.” This debate has been revived at various times in recent years, including in the run-up to the 2011 NATO-led Libya intervention, and during the ongoing Syrian civil war. While Russian officials have at times cited humanitarian intervention as grounds for the invasion of Ukraine, Western analysts say the war is a clear violation of international law.

What criticisms has the Security Council faced?

Many critics, including member states from the developing world, charge that the Security Council’s structure does not reflect current geopolitical realities. Its membership was expanded from six elected members to ten in 1965, and, in 1971, the People’s Republic of China took the permanent seat previously occupied by the Republic of China (Taiwan). Since then, the body’s composition has remained unchanged.

Regional powers such as Brazil, Germany, India, Japan, Nigeria, and South Africa have sought to enlarge the Security Council or secure permanent seats of their own. Others have called for France to cede its permanent seat to the European Union in the wake of Brexit, especially after France and Germany decided to share the presidency of the Security Council for two months in 2019. In 2021, Britain announced its support for Germany receiving a permanent seat. And in early 2023, China, France, and Germany called for two permanent seats for Africa on the Security Council. So far, calls for reform have not been heeded, with many countries instead seeking to diversify their diplomatic efforts through increased involvement with coalitions outside of the United Nations, such as the Group of Twenty (G20), a bloc of many of the world’s largest economies. The debate about expansion is often framed as a trade-off between legitimacy and efficacy. Saudi Arabia took the unprecedented step of declining a nonpermanent Security Council seat in 2013, announcing a day after it was elected to a 2014–15 term that it would not serve in the absence of institutional reform.

Other critics include advocates of R2P, who say the veto gives undue deference to the political interests of the P5, leading to inaction in the face of mass atrocities. Russia’s two vetoes of Security Council action on Ukraine, for instance, have spurred calls to kick Russia out of the P5. This line of criticism was growing even before the invasion; Zeid Ra’ad al-Hussein, the UN human rights chief from 2014 to 2018, repeatedly criticized the outsize power of the veto-wielding member states, warning that without institutional change, the United Nations could collapse.

But it is not just P5 members who have demonstrated reluctance to use force. Aspirants to permanent-member status, including Brazil, Germany, and India, have generally opposed interventions as violations of sovereignty. While R2P advocates criticize the Security Council and its members for a lack of political will, others question the United Nations’ conflict-management capacity, often citing 1990s peacekeeping crises in Rwanda, Somalia, and the former Yugoslavia. Recently, the United Nations has faced scrutiny over its ability to provide aid to Palestinians in the Gaza Strip, with critics saying that delays and watered-down support for a cease-fire have rendered the body’s response “woefully insufficient.” Calls to reform the Security Council grew stronger after China, Oman, and Turkey condemned the U.S. decision to block a cease-fire resolution, the only member to do so.

In the shadow of its 1993 experience in Somalia, in which eighteen U.S. Army Rangers were killed in an attempt to capture a warlord, the United States was among the powers that prevented a robust UN response in Rwanda. Despite alarming reports received by the Security Council in 1994, it declined to respond as an estimated eight hundred thousand people were killed in a genocide committed against ethnic Tutsis.

The United Nations also suffered humiliating defeats in the Balkans, where peacekeepers were used as human shields in the siege of Sarajevo and failed to protect civilians in the designated safe area of Srebrenica from massacre. Experts say these missions were undermined by both logistical and political problems, including muddled mandates, inadequate resources, and the parochial interests of major powers. In an effort to combat these and other problems, delegates have advocated for more transparency and efficiency in the Security Council’s decision making process, as well as more interaction with the General Assembly. 

Peacekeeping mandates continue to be scrutinized for their scope, cost, and cases in which peacekeepers themselves have committed abuses. A 2000 self-evaluation, commissioned by Annan and led by veteran envoy Lakhdar Brahimi, said the United Nations had “repeatedly failed,” and would continue to do so absent “significant institutional change and increased financial support.” Peacekeepers deployed in Haiti, for example, have faced intense criticism for widespread sexual exploitation, as well as for sparking a cholera outbreak that has killed some ten thousand people since 2010.

However, many experts say the United Nations’ overall track record is relatively strong: recent studies have found that, in general, UN peacekeeping prevents the resumption of violence in postconflict scenarios.

What are the prospects for reform?

The odds of substantial reform are seen as remote because amending the UN Charter requires an affirmative vote and domestic ratification by two-thirds of UN member states. This includes all of the Security Council’s permanent members, which are unlikely to take measures that would curb their own influence. While there is broad agreement among UN members that the Security Council’s makeup is outdated, each of the various proposals for reform inevitably leaves some aspirants alienated. Some proposals call for additional permanent members and others for a new class of elected seats that have the possibility of renewal. In the absence of charter reform, smaller states have advocated for procedural changes, including greater transparency and closer consultations with troop-contributing countries.

Still, in early 2022, then UN General Assembly President Csaba Kőrösi and U.S. President Joe Biden both said that reforming the Security Council should be an important objective. In his 2023 address to the United Nations, Biden elaborated on his previous calls for reform, urging the expansion of the Security Council, particularly by adding more members from Africa and Latin America.

Recommended Resources

The United Nations maintains a list of P5 vetoes from 1946 to the present.

These Backgrounders look at the UN General Assembly and how the United States funds the United Nations.

The National Interest’s Wes Martin argues that the Security Council needs to reform its peacekeeping efforts in Africa. 

CFR Senior Fellow Elliot Abrams argues against reforming the Security Council in this blog post.

For Foreign Affairs, PEN America’s Suzanne Nossel argues that the world still needs the United Nations.

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Rhea Basarkar, Sara Ibrahim, Nathalie Bussemaker, and Zachary Rosenthal contributed to this report. Will Merrow created the graphics.

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