What Is NATO?

NATO Explained

how does nato work? It offers protection of freedom and stability for members and their regions; NATO targets include weapons of mass destruction, terrorism, and cyber-attacks; NATO protection does not extend to civil wars or internal coups; When one NATO nation is attacked, all NATO nations will retaliate; NATO is funded by its members, with the U.S. contributing roughly 75% of NATO's budget.

The Balance / Hilary Allison


NATO (North Atlantic Treaty Organization) is an alliance of 30 countries, as of September 2022, that border the North Atlantic Ocean. The Alliance includes the United States, most European Union members, the United Kingdom, Canada, and Turkey.

Key Takeaways

  • The North Atlantic Treaty Organization (NATO) is a 30-member alliance formed in the wake of World War II with the goal of protecting democratic freedom.
  • NATO includes the U.S. and Canada, as well as dozens of nations in Europe.
  • In addition to the core NATO alliance, NATO has partnerships with countries in other regions.

Definition and Examples of NATO

The North Atlantic Treaty Organization is a national security alliance among the U.S., Canada, and their European allies. It was formed in the wake of World War II to keep the peace and encourage political and economic cooperation on both sides of the Atlantic Ocean.

  • Acronym: NATO


While NATO is primarily a national security alliance, it also aims to promote stable economies in Europe and North America.

One example of NATO in action came in the wake of the September 11 attacks on the World Trade Center and the Pentagon. NATO collectively responded, and many NATO allies deployed military forces to Afghanistan. In 2003, NATO took command of an international security assistance effort in the country.

Who Is in NATO?

NATO's 30 members, as of September 2022, are Albania, Belgium, Bulgaria, Canada, Croatia, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, Montenegro, the Netherlands, North Macedonia, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Turkey, United Kingdom, and the U.S.

Each member designates an ambassador to NATO as well as officials to serve on NATO committees and discuss NATO business. These designees could include a country’s president, prime minister, foreign affairs minister, or head of a defense department.

On Dec. 2, 2015, NATO announced its first expansion since 2009, offering membership to Montenegro. Russia responded by calling the move a strategic threat to its national security. Russia is worried by the number of Balkan countries along its border that have joined NATO. North Macedonia, another Balkan country, joined NATO in 2020.

How Does NATO Work?

NATO's mission is to protect the freedom of its members and the stability of their regions. Its targets include weapons of mass destruction, terrorism, and cyber-attacks.

One key aspect of NATO is Article 5, which states, "The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all." In other words, an attack on one NATO nation will cause all NATO nations to retaliate.


NATO has invoked Article 5 just once in its history, following the 9/11 terrorist attacks on the U.S.

NATO's protection does not extend to members' civil wars or internal coups. During a 2016 coup attempt in Turkey, for example, NATO did not intervene on either side of the conflict. As a NATO member, Turkey would receive its allies' support in the case of an attack, but not in case of a coup.

NATO is funded by its members. The U.S. contributes roughly three-fourths of NATO's budget. Only nine countries were estimated to reach the target spending level of 2% of gross domestic product (GDP) for 2022. The U.S. was forecast to spend 3.47% of its GDP on defense in 2022.

NATO Activities

NATO conducts crisis management operations around the world. It leads military and surveillance operations in Kosovo and the Mediterranean. It trains security forces in Iraq. NATO conducts air policing missions in coordination with the African Union. NATO also carries out disaster relief operations and assists with the response to the refugee and migrant crisis in Europe.

NATO History

The founding members of NATO signed the North Atlantic Treaty on April 4, 1949. It worked in conjunction with the United Nations, the World Bank, and the International Monetary Fund. The UN came into existence in 1945, and the World Bank and the IMF were created during the 1944 Bretton Woods Conference.

NATO's primary purpose was to defend member nations from threats by communist countries. The U.S. also wanted to maintain a presence in Europe. It sought to prevent a resurgence of aggressive nationalism and to foster political union. In this way, NATO made the formation of the European Union possible. U.S. military protection gave European nations the safety needed to rebuild after World War II's devastation.


During the Cold War, NATO's mission expanded to prevent nuclear war.

After West Germany joined NATO, the communist countries formed the Warsaw Pact alliance, which included the USSR, Bulgaria, Hungary, Romania, Poland, Czechoslovakia, and East Germany. In response, NATO adopted the "Massive Retaliation" policy. It promised to use nuclear weapons if members of the Pact attacked. NATO's deterrence policy allowed Europe to focus on economic development. It didn't have to build large conventional armies.

The Soviet Union continued to build its military presence. By the end of the Cold War, it was spending three times what the U.S. was spending, with only one-third of the economic power. When the Berlin Wall fell in 1989, it was due to economic as well as ideological reasons.


In 1997, the NATO-Russia Founding Act sought to build bilateral cooperation between the two forces. In 2002, they formed the NATO-Russia Council to partner on shared security issues.

The collapse of the USSR led to unrest in its former satellite states. NATO got involved when Yugoslavia's civil war became genocide. NATO's initial support of a United Nations naval embargo led to the enforcement of a no-fly zone. Violations then led to airstrikes until September 1995, when NATO conducted a nine-day air campaign that ended the war. By December of that year, NATO deployed a peacekeeping force of 60,000 soldiers. That ended in 2004 when NATO transferred the function to the European Union.

Working Structures

NATO's command structure includes Chiefs of Defense from all member countries. The command structure is broadly broken down into two strategic command organizations, the Allied Command Operations (ACO) and the Allied Command Transformation (ACT). ACO headquarters are located in Belgium, Italy, and the Netherlands. The main ACT headquarters is in Norfolk, Virginia, but there are analysis and learning centers in Portugal, Poland, and Norway.


NATO participates in three alliances that expand its influence beyond its 30 member countries. The first is the Euro-Atlantic Partnership Council, which helps partners become NATO members. It includes 20 non-NATO countries that support NATO's purpose. It began in 1997.


NATO itself admits that "Peacekeeping has become at least as difficult as peacemaking." As a result, NATO is strengthening alliances throughout the world.

The Mediterranean Dialogue seeks to stabilize the Middle East. Its non-NATO members include Algeria, Egypt, Israel, Jordan, Mauritania, Morocco, and Tunisia. It began in 1994. 

The Istanbul Cooperation Initiative works for peace throughout the larger Middle East region. It includes four members of the Gulf Cooperation Council: Bahrain, Kuwait, Qatar, and the United Arab Emirates. It began in 2004.

NATO also cooperates with nine other countries on joint security issues. Five of them are Asia-Pacific countries, which include Australia, Japan, the Republic of Korea, Mongolia, and New Zealand. There is one in South America (Colombia), and there are three cooperative countries in the Middle East: Afghanistan, Iraq, and Pakistan.


In August 2021, NATO suspended support for Afghan authorities because of concern about violence and reports of human rights violations.

Notable Happenings and Key Events of NATO

Following Russia's military assault on Ukraine, NATO condemned Russia for its action and also the nation of Belarus for its participation in the attack. In its statement, the organization reiterated its commitment to Article 5 of the treaty (which does not extend to Ukraine, as it is not a NATO member).

At its meetings in July 2018, NATO approved new steps to contain Russia. These include two new military commands and expanded efforts against cyber warfare and counter-terrorism as well as a new plan to deter Russian aggression against Poland and the Baltic States.


In June 2022, NATO invited Finland and Sweden to become NATO members.

During the 2016 meeting, NATO announced that it would increase its presence in the Baltic states and eastern Poland. It increased air and sea patrols to shore up its eastern front after Russia attacked Ukraine.

On Nov. 14, 2015, NATO responded to the terrorist attacks in Paris. It called for a unified approach with the European Union, France, and NATO members. France did not invoke NATO's Article 5, which would have been a formal declaration of war upon the Islamic State group (ISIS). France preferred to launch airstrikes on its own.

NATO responded to U.S. requests for help in the war in Afghanistan. It took the lead from August 2003 to December 2014. At its peak, it deployed 130,000 troops. In 2015, it ended its combat role and began supporting Afghan troops. In June 2021, it announced it would withdraw those support forces, as well.

Frequently Asked Questions (FAQs)

Is Russia part of NATO?

Russia is not a part of NATO. NATO has a history of tension with Russia, despite partnering on some issues through the NATO-Russia Council.

Which country is the newest member of NATO?

On March 27, 2020, North Macedonia became the newest and 30th member of NATO.

Why is Ukraine not in NATO?

As an emerging democracy, Ukraine has been a strong partner with NATO. It has met several, but not all, criteria required to become a member nation.

How much money does the U.S. contribute to NATO?

Out of 30 countries, the U.S. contributes approximately 16% of NATO's common funding. It also spends the most on defense.

Was this page helpful?
The Balance uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Institute for Geopolitics, Economy, and Security. "NATO Membership Brings Stability and Economic Growth."

  2. North Atlantic Treaty Organization. “A Short History of NATO.”

  3. North Atlantic Treaty Organization. "What Is NATO?"

  4. North Atlantic Treaty Organization. "Alliance Invites Montenegro To Start Accession Talks To Become Member of NATO."

  5. U.S. Government Publishing Office. "Senate Hearing 114-712, NATO Expansion: Examining the Accession of Montenegro."

  6. North Atlantic Treaty Organization. "What Is NATO?"

  7. North Atlantic Treaty Organization. "The North Atlantic Treaty."

  8. North Atlantic Treaty Organization. "Collective Defence - Article 5."

  9. North Atlantic Treaty Organization. "Statement by the NATO Secretary General on First Anniversary of Coup Attempt in Turkey."

  10. North Atlantic Treaty Organization. "Defence Expenditure of NATO Countries (2014-2022)," Page 8.

  11. North Atlantic Treaty Organization. "Operations and Missions: Past and Present."

  12. United Nations. "History of the United Nations."

  13. The World Bank. "Bretton Woods and the Birth of the World Bank."

  14. North Atlantic Treaty Organization. "What Was the Warsaw Pact?"

  15. Economic History Association. "Military Spending Patterns in History."

  16. North Atlantic Treaty Organization. "NATO-Russia Council."

  17. North Atlantic Treaty Organization. “A Short History of NATO.”

  18. North Atlantic Treaty Organization. "The NATO Command Structure."

  19. North Atlantic Treaty Organization. "Euro-Atlantic Partnership Council."

  20. North Atlantic Treaty Organization. “A Short History of NATO.”

  21. North Atlantic Treaty Organization. "Mediterranean Dialogue."

  22. North Atlantic Treaty Organization. "Istanbul Cooperation Initiative (ICI)."

  23. North Atlantic Treaty Organization. “Partners.”

  24. North Atlantic Treaty Organization. "Statement by NATO Foreign Ministers on Afghanistan."

  25. North Atlantic Treaty Organization. "Statement by the North Atlantic Council on Russia's Attack on Ukraine."

  26. North Atlantic Treaty Organization. "Brussels Summit Declaration."

  27. NATO. "Press Conference by NATO Secretary General Jens Stoltenberg Following the Meeting of the North Atlantic Council at the Level of Heads of State and Government (2022 NATO Summit)."

  28. North Atlantic Treaty Organization. "NATO’s Military Presence in the East of the Alliance."

  29. North Atlantic Treaty Organization. "NATO Secretary General Condemns Terrorist Attacks in Paris."

  30. Center for Strategic and International Studies. "After the Paris Attacks, France Turns to Europe in Its Time of Need."

  31. North Atlantic Treaty Organization. “NATO and Afghanistan.”

  32. North Atlantic Treaty Organization. "North Macedonia Joins NATO as 30th Ally."

  33. North Atlantic Treaty Organization. "Relations With Ukraine."

  34. Taxpayers for Common Sense. "U.S. Contributions to NATO Budgets."

  35. North Atlantic Treaty Organization. "Funding NATO."

Related Articles