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The Formation of NATO

The Formation of NATO

On 4 April 1949, capitalist countries from the Northern hemisphere came together to form a military alliance called the North Atlantic Treaty Organisation (NATO). Its main objective was to encourage the countries to work together and to provide collective security to the US, Canada, and the Western European countries against the communist Soviet threat.

Although this alliance has transformed throughout the years, it exists to this very day and remains one of the most influential products of the Cold War on twentieth and twenty-first-century international relations.


An association to help further the common interests of its members.


An agreement or arrangement negotiated and signed by two or more authorities (i.e. states, countries, leaders).

The formation of NATO summary

After the Second World War, Europe was devastated. Many countries had very weak economies and had dramatically reduced armies. This left them both militarily and ideologically vulnerable.

The Soviet Union emerged from the war with a far bigger breadth of power, having installed armies across the states of Central and Eastern Europe. Stalin’s Iron Curtain had descended across Europe as the USSR built up a buffer zone by installing communist governments in Eastern European countries. This buffer zone safeguarded the USSR from any attacks from the West.

The Western allies feared that the Soviets might want to expand this buffer zone by capturing more countries in Europe through the appeal of communism or military domination.

Iron curtain

A metaphor used by Winston Churchill to describe the area isolated by the Soviet Union.




Appeal of Communism

Countries with failing economies and poor living conditions were more vulnerable to the ideological appeal of communism and may turn to it.

  • Economic aid to European countries with a focus on recovery and rebuilding.

  • This would make communism look less favourable.

How: The Marshall Plan


Smaller weaker countries with reduced militaries and weapons were more vulnerable to Soviet invasion and could be dominated.

  • Military alliance to create a collective defence, arm countries, and rebuild militaries.


  • The Western Union
  • NATO

Monetary aid from the Marshall Plan was helping to rebuild and develop strong economic ties between countries. However, many felt that economic prosperity was not enough to stave off the Soviet threat and that the countries needed greater military cooperation to ensure that some of the smaller and more vulnerable countries in Western Europe were protected- this led to the formation of NATO.

Reasons for the formation of NATO

We now know the main reason for the formation of NATO- protection from Soviet aggressive expansionism. This was compatible with the US Policy of Containment stressed by the Truman Doctrine.


A policy of containing the Soviet threat by not allowing the USSR to gain power over any more countries.

Let's look more in detail at events leading up to NATO's formation in 1949.

The coup d’état in Czechoslovakia

In February 1948, the Communist Party of Czechoslovakia took complete undisputed control of the government of Czechoslovakia. As Czechoslovakia was the last Eastern European democracy, it shocked the Western world and consolidated the USSR’s power.

Fearing the Soviet’s increasing stronghold, it spurred Western European countries to start discussing collective defence to protect other countries.

Coup d’état

A violent overthrow or alteration of an existing government by a small group.

The Formation of NATO Pro-communist demostrations in Czechoslovakia StudySmarterPro-communist demonstrations in the country before the coup, Wikimedia Commons.

The Berlin Blockade

The Berlin Blockade of 1948 demonstrated that the Western and Eastern zones could not peacefully co-exist and that the USSR was a volatile and unpredictable force in the Cold War. It showed what the Soviet Union was capable of and stressed the need for a defensive organisation in case they tried similar stunts in other European countries.

Increased US presence in Europe

The Cold War tensions and the acceleration of the nuclear arms race made it more important for the US to have influence and presence in Europe. In the event of a Soviet attack on any of the capitalist European states, the US could intervene quickly and effectively if they had military bases in Europe. Establishing NATO enabled them to place weapons and potentially nuclear missile sites in their member states that were closer to the USSR.

China and North Korea

The USA was becoming increasingly worried about the spread of communism following China’s Communist Revolution in 1949. The world was looking increasingly ‘red’, and this power could threaten the Western world. This fear was further compounded by North Korea becoming a fully-fledged communist state in 1949 and the subsequent Korean War. This encouraged the NATO allies to create a military structure with headquarters in Paris.

The formation of NATO

In 1948, Britain, France, Belgium, the Netherlands, and Luxembourg had created the Brussels Treaty, which assured mutual defence. However, these states recognised that they would need to create a stronger and larger alliance to counter the threat of the Soviets.

Britain, Canada, and the US engaged in talks in March 1948 about a collective defence organisation to enhance security and promote democratic values. France, Belgium, Luxembourg, the Netherlands, and Norway joined these talks in 1949. From there, the North Atlantic Treaty was formed.

Member States

  • 1949: The original members were the USA, Canada, Britain, France, Belgium, Holland, Luxembourg, Norway, Iceland, Denmark, Italy, and Portugal.

  • 1952: Greece and Turkey joined.

  • 1955: West Germany joined.

  • 1982: Spain joined.

The purpose of NATO

NATO created an alliance of countries that would work cooperatively to build up their militaries and support each other in the event of an attack. The articles within the treaty, signed by its members, all work to support these purposes:

  • Provide collective defence to members

  • Prevent Soviet expansionism

  • Encourage European cooperation

  • Maintain a US presence in Europe

  • Prevent a revival of nationalist militarism

Article 5

The treaty consists of 14 articles, outlining how countries will support each other militarily. Article 5, however, is arguably the most important of the NATO alliance as it enshrines collective defence. It states that

an armed attack against one Ally is considered an attack against all Allies.

This means that if one NATO member is attacked then all NATO nations will respond.

Did you know?

Article 5 has actually only been invoked once so far since the creation of NATO in 1949. Do you know which major event of the twenty-first century provoked this? (Answer below).

Formation of NATO and the Cold War

The formation of NATO further deepened the split between capitalist and communist powers. As NATO was a defensive rather than offensive strategy, however, there was no real threat to the USSR, hence it did not immediately create its own military alliance.

In 1954, the Soviet Union actually suggested it should join NATO to help preserve peace in Europe. However, its offer was rejected as the other members felt there was an ulterior motive to weaken the treaty.

It was West Germany’s 1955 admission into NATO that pushed the USSR into forming their own version, the Warsaw Pact; West Germany was allowed to join NATO and permitted an army and air force. This worried the USSR, who felt that it may lead to a renewal of Germany’s strength and power. The Second World War had only ended ten years earlier and its brutality was fresh in the minds of many who had fought, lost people, or suffered its long-term consequences.

In response, the USSR created its own military alliance- the Warsaw Pact. West Germany joining NATO was a turning point in the Cold War; with the formation of the Warsaw Pact including East Germany, the Iron Curtain was well and truly established.

The formation of the Warsaw Pact

On 14 May 1955, the communist states of Eastern Europe came together to form a military alliance with similar security aims to NATO. Relations among those who signed the treaty were based upon mutual non-intervention in the internal affairs of the member countries, respect for national sovereignty, and political independence. Member states were also obligated to intervene if any of the Warsaw Pact countries were threatened.

Member States

The original members were the USSR, East Germany, Poland, Hungary, Czechoslovakia, Romania, Bulgaria, and Albania.

Yugoslavia, although a communist state, notably refused to join the Warsaw Pact. Tito, Yugoslavia's leader, had always wanted independence from Stalin.

The Formation of NATo Military alliances map during the Cold War StudySmarter

Map of the military alliances in Europe during the Cold War. Created with - StudySmarter.

Consequences of the formation of NATO and the Warsaw Pact

There was never any direct confrontation between NATO and the Warsaw Pact, but the threat of nuclear war was enough to deter them from attacking each other.

‘Massive retaliation’

NATO adopted the doctrine of ‘Massive Retaliation’ if the Soviet Union attacked. This meant that they would respond with nuclear weapons for even the smallest of transgressions. This prevented either side from taking any risks as the consequences would be extreme.

The NATO alliance members could, as a result, focus on economic growth rather than building large armies. Members could also focus on scientific and political cooperation (such as the Space Race) rather than solely military.

The Warsaw Pact and the invasion of Czechoslovakia

When Czechoslovakia threatened the stability of the Eastern bloc in 1968 by relaxing some restrictions in what was known as the Prague Spring, the USSR invaded the country using troops from the Warsaw Pact. Every member of the Warsaw Pact (excluding the Socialist Republic of Romania and the People’s Republic of Albania) participated, quickly and effectively crushing the Prague Spring.

This single demonstration of the power of the Warsaw Pact tightened the USSR’s control of its states. They could attribute the invasion to the Warsaw Pact countries rather than just the USSR and it deterred any other Eastern bloc countries from rebelling against the USSR for years.

Did you know? (Answer)

Article 5 has so far only ever been invoked in the aftermath of the 9/11 attacks to fight terrorism.

The formation of NATO - Key takeaways

  • NATO was formed in 1949 by the US, Canada, and West European countries.
  • Its main purposes were to create collective security against the Soviet threat, maintain a US presence in Europe, and encourage collaboration between European states.
  • Article 5 is the most important part of the treaty, as it stipulates that ‘an armed attack against one Ally is considered an attack against all Allies.’
  • West Germany’s accession to NATO in 1955 compelled the Soviet Union to create their own military alliance, the Warsaw Pact.
  • NATO and the Warsaw Pact never directly confronted each other. Instead, they contributed to the long cold standoff during the Cold War.
  • The Warsaw Pact was used to invade Czechoslovakia during the Prague Spring in 1968, strengthening the USSR’s control over its states.

Frequently Asked Questions about The Formation of NATO

The formation of NATO was when on 4 April 1949, capitalist countries from the Northern hemisphere came together to form a military alliance. This alliance aimed to provide collective security, namely against the Soviet Union, and stated that the countries would support each other if one country was attacked. The original member states were the USA, Canada, Britain, France, Belgium, Holland, Luxembourg, Norway, Iceland, Denmark, Italy, and Portugal.

The formation of NATO happened due to increasing tensions between East and West and the US becoming concerned about the Soviet’s growing power. The main catalyst was, however, when the USSR blockaded the West’s two main trade corridors to West Berlin for 11 months. This demonstration of power threatened conflict between the USA and the USSR, hence prompting them to ensure they had an effective defence strategy.

NATO was formed in the aftermath of a coup d’état in Czechoslovakia when the Western Allies Britain, Canada, and the US went into talks on how they could strengthen Europe’s defence against the Soviets.  France, Belgium, Luxembourg, the Netherlands, and Norway joined these talks in 1949. NATO was then formed, with the USA, Canada, Britain, France, Belgium, Holland, Luxembourg, Norway, Iceland, Denmark, Italy, and Portugal as its original member states.

According to NATO, three purposes for which it was formed were: preventing Soviet expansionism, stopping the revival of nationalist militarism in Europe through US presence, and encouraging European cooperation and political integration.

NATO developed the Cold War as it established a clear Western capitalist defence strategy and caused the Eastern communist states to create their own in the form of the Warsaw Pact. These two alliances demonstrated that there were two clear sides, which would intervene if any of their members were in danger. The threat of intervention arguably prevented the sides from invading new states and expanding. The Warsaw Pact was used to quell uprisings like the Prague Spring in the 1960s.

Final The Formation of NATO Quiz


What were the Western powers concerned might happen to their states in the aftermath of the Second World War? (Choose two answers)

Show answer


They would turn to communism

Show question


What two of these circumstances made the Western states vulnerable to the USSR? (Choose two answers)

Show answer


Stalin’s great economic power

Show question


Explain how the US could prevent European countries from turning to communism.

Show answer


Economic aid to European countries with a focus on recovery and rebuilding would make communism look less favourable. They did this in the form of the Marshall Plan.

Show question


Which of these countries were original members of NATO? (Choose three)

Show answer



Show question


Which of these belong among the purposes for the formation of NATO? (Choose two)

Show answer


 Encourage European cooperation

Show question


Explain why article 5 is so important in the NATO treaty.

Show answer


Article 5 is so important because it enshrined collective defence. The statement ‘an armed attack against one Ally is considered an attack against all Allies’ means that if one NATO member is attacked, then all NATO nations will retaliate.

Show question


What did the Truman Doctrine have to do with the formation of NATO?

Show answer


The Truman Doctrine promoted a US Policy of Containment towards the USSR. This policy meant that the US would try to prevent the USSR from gaining control of any more countries. The threat of Soviet expansionism was one of the causes of the formation of NATO, which would ultimately support the US in not allowing communism to spread.

Show question


Why were Czechoslovakia and West Berlin factors in the formation of NATO?

Show answer


In 1948 a coup d’état gave the USSR power over Czechoslovakia, removing the final Eastern European democracy. The Allies became worried about increasing Soviet influence. West Berlin was important due to the Berlin Blockade of 1948, where the USSR cut off trade corridors to West Berlin. This demonstrated the volatility of the USSR, its power, and threatened war. NATO was introduced to prepare the Western countries for this eventuality.

Show question


Why was it important for the US to have a presence in Europe? (Choose three options)

Show answer


To free Eastern European countries from communism

Show question


How did China and North Korea influence the formation of NATO?

Show answer


A reason for the formation of NATO was that the USA was becoming increasingly worried about the spread of communism. China’s Communist Revolution in 1949 and North Korea’s turn to communism in 1950 compounded this, making NATO more urgent and encouraging them to focus on creating a real military power.

Show question


Which of these countries were members of the Warsaw Pact? (Choose two)

Show answer



Show question


What event in 1955 compelled the USSR to create the Warsaw Pact and why?

Show answer


In 1955 West Germany was allowed to join NATO and permitted an army and air force. This concerned the USSR as they worried about Germany regaining their power.

Show question


What does the term ‘Massive Retaliation’ mean and how did it affect relations?

Show answer


The US adopted this doctrine, meaning that they would respond with nuclear weapons if the USSR attacked in any way. This threat prevented either side from taking risks and meant that countries could focus on economic development and other avenues rather than building up their military.

Show question


How was the Warsaw Pact utilised to exert Soviet control over Czechoslovakia in 1968?

Show answer


During the Prague Spring, where a relaxation of restrictions threatened the Soviet Union’s control, the Soviet Union ordered the Warsaw Pact countries to invade. The use of these countries tightened the USSR’s control over its states by deterring any future rebellions.

Show question


Did the Warsaw Pact and NATO ever directly confront each other?

Show answer


No, they remained in a long standoff during the Cold War until the end, mainly due to the threat of nuclear weapons.

Show question


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