What is NATO, what is it for, and which countries are part of it today?

NATO returns to the center of international debate whenever the world experiences geopolitical tension. Unfortunately, this has happened quite often in recent years, especially in connection with Russia’s invasion of Ukraine, but today the situation has become even more complicated with the conflict involving Iran and several Middle Eastern countries. In a crisis like the one we are currently experiencing, even a single incident—like the Iranian missile aimed at Turkish airspace and intercepted by the alliance’s defenses—can raise enormous questions: What happens if a NATO state is attacked? Does the alliance intervene automatically? And who decides?

These are far from theoretical questions. Turkey is, in fact, a member of the organization, and a potential large-scale attack against its territory could trigger Article 5 of the North Atlantic Treaty, the principle that provides for collective defense among members. However, this is not an automatic mechanism: the decision must be made by the Atlantic Council, and each member of the alliance can contribute differently, not necessarily by sending troops.

This scenario is part of an increasingly unstable international context. In addition to the conflict in Ukraine, the Middle East is experiencing tensions involving Israel, Iran, Lebanon, and several other regional players. The possibility that these crises could spill over to directly involve Western allies is a major concern for the international community.

It is precisely in situations like these that NATO plays a crucial role. Born at the height of the Cold War to guarantee the security of Western countries, the alliance has gradually transformed into one of the main pillars of the global geopolitical balance. Today, it is more than just a military coalition: it is a system of political, strategic, and military cooperation involving dozens of countries and millions of soldiers.

To truly understand what it means to talk about NATO—and why this organization is central to international crises—we must begin with its origins, its principles, and the alliance’s practical functioning.

What is NATO? Meaning, Origin, and Founders

NATO, an acronym for North Atlantic Treaty Organization, is an international political-military alliance created to ensure the collective security of its members.

The underlying principle is simple yet extremely powerful: its member states pledge to defend each other in the event of external aggression.

The organization was officially born on April 4, 1949, when twelve countries signed the Washington Treaty, the document establishing the alliance at the height of Cold War tensions. At the time, the main fear of Western states was the expansion of the Soviet Union into Europe. NATO was therefore born as a means of defense of the Euro-Atlantic bloc against a possible Soviet offensive.

The twelve founding countries are:

• Belgium
• Canada
• Denmark
• France
• Iceland
• Italy
• Luxembourg
• Norway
• Netherlands
• Portugal
• United Kingdom
• United States

From the beginning, the alliance has had a dual dimension: political and military. On the one hand, it represents a permanent forum for cooperation between governments, on the other, it constitutes an integrated defense structure.

NATO’s headquarters are now located in Brussels, Belgium, while the main military command is located near Mons. Over the decades, the alliance has grown both in size and operational capabilities, from the original twelve members to the current 32 states.

After the end of the Cold War, NATO was not disbanded, as some had speculated. On the contrary, it expanded its activities and its area of intervention, participating in missions in the Balkans, the Middle East, South Asia, and Africa. This transformation process has progressively redefined the role of the organization, which today is no longer merely an instrument of military deterrence but also a central player in international crisis management.

NATO’s Purpose and Values

NATO, as mentioned, is based on a fundamental principle: to guarantee the freedom and security of member countries through political and military means. It is not merely a military alliance, but a system of collective security that aims to preserve international stability.

One of the organization’s core elements is the promotion of democratic values. Member states share a commitment to the rule of law, human rights, and the democratic control of armed forces. From this perspective, NATO also functions as a platform for political cooperation, where governments can discuss key strategic issues.

Another fundamental objective is conflict prevention. The alliance prioritizes diplomatic dialogue and international cooperation as tools for reducing tensions. Only when political efforts fail can the military dimension come into play.

The cornerstone of the entire system, however, is the principle of collective defense. This means that an attack against one member country is considered an attack against all. This mechanism is enshrined in Article 5 of the Washington Treaty, which represents the heart of the alliance.

In practice, however, the activation of Article 5 is not automatic. For it to be applied, an armed attack must occur, and a formal decision by the North Atlantic Council, NATO’s principal political body, is required. Furthermore, each state can decide how to contribute to the response: with troops, logistical support, military bases, or other forms of assistance.

So far, Article 5 has been invoked only once in history, after the terrorist attacks of September 11, 2001 in the United States. On that occasion, the allies supported the military intervention in Afghanistan, contributing to the operations in varying degrees.

Today, NATO can count on a total military force of approximately 3.5 million soldiers drawn from the armies of member countries. Its operational capabilities also include the NATO Response Force, a multinational force with high readiness that can be rapidly deployed in the event of a crisis.

NATO Member Countries Today

Since its inception in 1949, NATO has progressively expanded. Over the decades, several European countries have requested membership, especially after the end of the Cold War and the dissolution of the Soviet Union.

Today, NATO member countries number 32, spread across Europe and North America. The twelve founding members have been joined by new states that joined at different times in the alliance’s history.

Subsequent major additions include Greece and Turkey in 1952, Germany in 1955, and Spain in 1982. After the collapse of the Soviet bloc, the alliance expanded into Eastern Europe with the accession of, among others, Poland, Czech Republic, and Hungary in 1999.

An even more significant expansion came in 2004 with the accession of seven Central and Eastern European countries, including Estonia, Latvia, and Lithuania. Montenegro, North Macedonia, and other Balkan states also joined in subsequent years.

The latest major step in the alliance’s expansion occurred in the context of the war between Russia and Ukraine. After decades of neutrality, Finland and Sweden decided to join NATO in 2023 and 2024, respectively, bringing the total number of members to thirty-two.

Today, the alliance encompasses almost all of Western and Northern Europe, as well as two North American countries—the United States and Canada—which represent a key component of its military and strategic power.

Who are NATO’s partner countries (and how are they different from members)

Alongside the member states, there is a very large network of NATO partner countries. They are not formally part of the alliance and are not covered by the principle of collective defense, but they collaborate with the organization on various fronts, from security to military cooperation.

These partnerships are organized through various diplomatic and military programs.

One of the most important is the Partnership for Peace (PfP), created in 1994 to develop bilateral relations between NATO and the countries of Eastern Europe or the former Soviet Union. Among the countries involved are Ukraine, Georgia, Moldova, Armenia, and several Central Asian republics.

Then there is the Euro-Atlantic Partnership Council (EAPC), a dialogue forum that brings together numerous partner countries and allows for regular consultations on security issues.

Another initiative is the Mediterranean Dialogue, which involves states such as Egypt, Israel, Jordan, Morocco, Algeria, Mauritania, and Tunisia with the aim of strengthening stability in the region.

In the broader Middle East, the Istanbul Cooperation Initiative operates, which includes Bahrain, United Arab Emirates, Kuwait, and Qatar and promotes cooperation on security and counterterrorism.

Finally, there are the so-called Global Partners, countries that collaborate with the alliance despite not being European and therefore cannot formally join under the treaty’s rules. These include Japan, South Korea, Australia, New Zealand, Pakistan, Mongolia, and Iraq.

The main difference from members is clear: partners can participate in exercises, cooperation programs, and international missions, but are not bound or protected by Article 5. In other words, they cooperate with NATO, but are not part of the collective defense system.

Does NATO have its own army? When does it intervene?

One of the most frequently asked questions concerns precisely this point: does NATO have its own army? The answer is partly yes and partly no.

The alliance does not have standing armed forces in the traditional sense. Armies remain under the control of individual member states. However, NATO can rely on the combined armed forces of its member countries, which together comprise millions of soldiers.

When necessary, states make national contingents available for joint operations under NATO command. This system allows the alliance to rapidly mobilize very large military resources.

One of the main tools is the NATO Response Force, a multinational force with high operational readiness designed to intervene rapidly in crises or emergencies.

Alliance operations can be launched in various circumstances:

• application of Article 5 in the event of an attack on a member
• missions authorized by the United Nations
• crisis management or peacekeeping operations

In the case of collective defense, the decision-making process is very precise. If a state believes it has been attacked, it can request the activation of Article 5. The matter is then discussed by the Atlantic Council, which must decide unanimously.

Furthermore, not every incident can be considered an attack. For the collective defense clause to be activated, it must be a large-scale armed attack, not isolated or accidental incidents.

As mentioned, if Article 5 is applied, each alliance country decides independently how to contribute to the response. This flexible system allows NATO to adapt to very different scenarios, from traditional territorial defense to international stabilization missions.

Who can become a member of NATO? The Enlargement Hypothesis: Tensions and Strategies

The North Atlantic Treaty establishes precise criteria for the accession of new members. According to Article 10, any European State capable of respecting the principles of the alliance and contributing to the security of the North Atlantic area can be invited to join.

Accession, however, requires two fundamental conditions:

• the candidate country must meet a series of political and military requirements
• all member states must unanimously approve accession

To prepare candidates, there is a specific instrument called the Membership Action Plan (MAP), an assistance program that helps aspiring states reform their institutions and armed forces.

Among the main requirements are:

• Respect for the rule of law and human rights
• Democratic control of the armed forces
• Ability to contribute to the Alliance’s missions
• Legislative compatibility with NATO standards

Currently, several countries are considered aspiring members, including Bosnia and Herzegovina, Georgia, and Ukraine. However, the Alliance’s enlargement is a highly sensitive geopolitical issue, especially in relations with Russia, which considers NATO’s eastward expansion a threat to its security.

NATO and its role between wars: from Russia-Ukraine to Iran, via Gaza

In recent years, NATO has found itself at the center of a series of international crises that have redefined its strategic role.

The most significant conflict remains that between Russia and Ukraine, which began with the Russian invasion in 2022. While not intervening directly with its own armed forces, the alliance has provided strong political and military support to Kiev, while also strengthening its military presence on Europe’s eastern flank.

But today, international attention is increasingly shifting to the Middle East. The war involving Iran, Israel, and several regional players risks spreading far beyond the region’s borders. And the episode of the Iranian missile targeting Turkish airspace has brought the winds of war to the fore. Turkey is a NATO member: is there a possibility of Article 5 being triggered?

According to alliance leaders, the episode does not currently constitute grounds for invoking the collective defense clause. For that to happen, a genuine large-scale armed attack must occur, not an isolated incident or a missile aimed elsewhere.

Nonetheless, the episode demonstrates how delicate the situation truly is, especially given the potential for escalation. The Middle East conflict involves a growing number of countries—from Saudi Arabia to Lebanon, including the United Arab Emirates and Qatar—and risks turning into a broader international crisis.

The world is currently facing one of the most volatile times in decades, with multiple theaters of war active simultaneously: Ukraine, Israel-Palestine, and the conflict with Iran. And it is precisely in complex scenarios like these that the collective security system built by NATO could prove to be a true deciding factor.

Original article published on Money.it Italy. Original title: Cos’è la NATO, a cosa serve e i Paesi che ne fanno parte oggi