The North Atlantic Treaty Organization (NATO)

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


One of the most significant treaties of the post-Second World War era has been the North Atlantic Treaty, signed in 1949, which founded the North Atlantic Treaty Organization (NATO). The North Atlantic Treaty is a collective military security agreement that was signed at the start of the Cold War, with the aim of protecting its members from the threat of military (especially nuclear) attack from the Soviet Union and the Warsaw Pact countries.

The North Atlantic Treaty Organisation (NATO) was formed to provide collective security against the threat of military action in Europe from the Soviet bloc, and to promote deeper political integration and stability in Europe. Perhaps the most important article of the Treaty is Article 5, in which the signatories agree that an attack on one of them would be considered an attack on all of them, and that they should consider armed force in response.


By the end of the 20th Century NATO had lost its original purpose from the post-Cold War era, but the second Russian invasion of Ukraine (like the Balkans crises of the 1990s) stimulated NATO into a unified response. However, as the Ukraine War dragged on the allies’ divergent threat perceptions became apparent again. In April 2024 NATO chief Jens Stoltenberg proposed a $100 billion, five-year fund for Ukraine when alliance foreign ministers met the financial package will be part of a broader initiative to incentivize allies to support Kyiv, as a $60 billion U.S. military aid package is stalled in Congress. Poland and the Baltic states supported the plan but other members were hesitant. 

Questions for the future of NATO



Early role

At the end of the Second World War Europe was devastated: millions had been killed; millions more were displaced; and entire countries and economies were not working. It was feared that political instability would lead to communist parties winning elections. The Cold War was beginning. The USA had signaled its intentions with the Marshall Plan, designed to kick-start the economies of Europe and restore economic and political stability. Attempts to restore military security to Western Europe began with the Western Union in 1948, but it was felt that a truly North Atlantic approach – including the Americans – was needed. The Korean War and the Soviet Union’s detonation of an atomic weapon in 1949 triggered deeper military integration. Lord Ismay, NATO’s first secretary- general, supposedly said that NATO’s purpose was ‘to keep the Russians out, the Americans in and the Germans down’.

The Warsaw Pact

The Warsaw Pact (or Treaty of Friendship, Co-operation and Mutual Assistance) was formed in 1955 as a collective security organisation on the other side of the ideological divide from NATO in the Cold War. It was signed by seven countries under Soviet influence – Albania, Czechoslovakia, Poland, Hungary, Romania, Bulgaria and East Germany – as well as the Soviet Union itself.

NATO and Warsaw Pact countries never engaged in military conflict with each other, but the balance of power relations between these two blocs was the backdrop to much of the Cold War. Relations were oſten tense in a divided Europe – symbolised by the Berlin Wall, which was constructed in 1961 – but during the 1960s there was a movement towards détente (easing previously strained relationships).

Aſter the 1979 Soviet invasion of Afghanistan, tensions between NATO and the Warsaw Pact increased with a new arms race for ballistic missiles, which created division in western Europe. From 1985 the rise of Mikhail Gorbachev, who was happier to negotiate with the USA and its NATO allies, meant that the Cold War was coming to an end.

 Since 1949, NATO’s membership has increased from 12 to 32 countries through 10 rounds of enlargement. Sweden became the latest country to join the Alliance on 7 March 2024. Currently, three partner countries have declared their aspirations to NATO membership: Bosnia and Herzegovina, Georgia and Ukraine. Finland has been a NATO partner since 1994. Since its status changed to a full ally 2023. NATO remains popular in Finland, with approximately 89% of the population supporting the Alliance

Changing role

The end of the Cold War brought about an existential question for NATO, because the threat that NATO had been set up to counter had vanished. NATO was still committed to fighting militant nationalism in Europe, as well as promoting democracy and political integration. The ex-communist states of central and eastern Europe soon made it clear that they saw membership of NATO and the EU as key to embedding democracy and stability in their countries.

Involvement beyond Europe

NATO’s primary role was collective security in Europe, and with the decline of the Soviet Union, people started to question its role. However, NATO’s member states started to face different threats in the 21st century. On September 11th 2001, terrorists flew passenger airlines into the World Trade Towers in New York and into the Pentagon in Washington D.C. This triggered the first and only time that Article 5 of the NATO charter was invoked – this attack on one member state was an attack on all. These terrorist attacks provoked a huge reaction from America and its allies. In Operation Enduring Freedom, America led the invasion of Afghanistan in October 2001 to take control from the Taliban regime, which had allowed Al-Qaeda to use the country as a base. NATO was called on to take command of the International Security Assistance Force (ISAF), aiming to provide security and stability so that peace and democracy could flourish. NATO maintained a presence in the country from 2003 to 2014.

NATO’s role in Afghanistan was controversial:

• Military personnel from NATO countries suffered considerable casualties. More than 2000 US and 400 UK personnel were killed. These losses were politically damaging. It was hard to make the case that NATO, perceived to be a defence organisation for Europe, was acting defensively in Afghanistan. People questioned how NATO troops serving and dying in Afghanistan helped the national interests of the member states.

• There were a number of ‘friendly-fire’ incidents in Afghanistan.

• Civilians were killed, particularly in airstrikes by NATO aircraſt, such as the bombing of a wedding party by a US air raid in 2008. On top of the suffering, these casualties caused tensions between the Afghan government and foreign forces, and controversy among other NATO nations.

Growth and expansion into Eastern Europe and implications for peace and stability The first expansion of NATO into former Warsaw Pact countries followed the reunification of Germany. As the Cold War came to an end, former Eastern bloc countries had ambitions to join both NATO and the EU. From 1990, 12 states from central and eastern Europe joined NATO; ten were former Warsaw Pact members and two were former republics of Yugoslavia. Crucially, many states saw the Cold War as a period of oppression by the Russians in the guise of the Soviet Union. These new democracies were determined to entrench their freedom from Russia as well as their political and economic freedoms. Democracy, peace and stability would be ensured by a collective security arrangement with other European states and the sole superpower, the USA.

All 12 states that have joined NATO since the Cold War also wanted to join the European Union, and all but Albania have done so. Membership of NATO would guarantee security, while membership of the EU would embed democracy, human rights and market economies in those countries.

For Russia, this expansion of NATO into its former sphere of influence was not only a threat but also a betrayal. The Russians believed that the deal to bring about German reunification prohibited the expansion of NATO into central and eastern Europe. This expansion is seen by Moscow as part of the West’s policy to ‘encircle’ and isolate Russia.

Relationship with Russia and the wider world

NATO’s relationship with Russia and its predecessor the USSR has always been strained. In recent years, concerns about Russia’s objectives in its ‘near abroad’ have raised tensions in the region to what some have described as a new Cold War.

Aſter the collapse of the Soviet Union, Russia was not in a position to confront the power of the USA – economically, militarily or politically – so NATO did not feel under threat. As NATO took in more European countries and many joined the EU, Europe seemed like a haven of peace and stability. However, recently there have been several crises and tensions between Russia and NATO as Vladimir Putin has tried to regain Russia’s position as a global power. Enlargement of NATO has caused disquiet and anger in Moscow, but there have been other issues where NATO and Russia have different interests, such as the USA’s placement of an anti-ballistic missile system in former

Soviet-bloc countries near Russia. The US maintains that the system is designed to protect against missiles from Iran and North Korea, but the Russians have their suspicions. The 2008 military conflagration between Russia and Georgia raised tensions, and Russia has sided with Serbia, its historic ally, over Kosovo’s secession and pursuit of independence.

More recently, Russian actions in Ukraine – not a NATO member – caused alarm in the West. In March 2014, Russia annexed the Crimean peninsula, which belongs to Ukraine. Russian support for pro-Russian rebels and its actions in the Donbass region of eastern Ukraine are also a sign of the dangers that Russia poses. Russia is rearming and has used its military to support President Assad in the Syrian Civil War. NATO allies, particularly those with bitter memories of Soviet domination, are concerned that President Putin’s tactics against Ukraine could be used against them too.

Poland and the Baltic states are concerned about Russia’s tactics, including using hybrid warfare – a mixture of conventional warfare, subversive and destabilising activities, and cyber-warfare – that could test the collective security commitments of the 28 member states of NATO. They fear that the Russians could manufacture a crisis involving ethnic Russian minorities in the Baltic states to muddy the waters, allowing Russia to intervene with troops who are not attributable to Russia (as occurred in Ukraine). In such a circumstance, Russia could plausibly deny responsibility, thus forcing NATO countries to decide whether to retaliate with limited evidence of the Russian state’s involvement. Any differing views within NATO would massively weaken the alliance and give strength to the Russians. The stakes are high and both Russia and NATO have sought to bolster their borders by bringing in troops and military equipment to deter what each side sees as an aggressive neighbour. These movements suggest a re-play of the Cold War and a classic security dilemma and arms race.Other countries in the neighbourhood of NATO and further afield have partnerships and dialogues with the bloc. Some of these are prospective members like Georgia; others are members of the EU but not members of NATO, like Sweden, Finland and Austria. Cyprus is a unique case because it is a member of the EU but is unlikely to join NATO in the near future, as Turkey would veto its membership.

NATO has quite close relationships with the EU as they share many member states, values and interests. Close co-operation between NATO and the EU can make the best use of the two organisations’ specialisms. NATO can do much of the military work that the EU cannot do, while the EU has civilian expertise and soſt power. One example of close co-operation was the two organisations deploying naval forces side-by-side in anti-piracy operations off the coast of Somalia.

More recently, Russian actions in Ukraine – not a NATO member – caused alarm in the West. In March 2014, Russia annexed the Crimean peninsula, which belongs to Ukraine. Russian support for pro-Russian rebels and its actions in the Donbass region of eastern Ukraine are also a sign of the dangers that Russia poses. Russia is rearming and has used its military to support President Assad in the Syrian Civil War. NATO allies, particularly those with bitter memories of Soviet domination, are concerned that President Putin’s tactics against Ukraine could be used against them too.


Is NATO still relevant?

Since the end of the Cold War, some have questioned the continuing relevance of NATO. Certain US politicians have questioned the USA’s commitments to NATO, sentiments that President Donald Trump expressed in the 2016 US presidential election campaign. The USA currently accounts for 70% of NATO member states’ defence budgets, reflecting its far larger military power and historic influence. Critics in Washington, DC complain that NATO is over-reliant on the USA and that the USA is subsidising European defence budgets. Despite NATO countries agreeing to spend 2% of their GDP on defence, and this being a condition of membership, in 2015 only five states — Estonia, Greece, Poland, the UK and the USA — met this commitment. While the Cold War may have ended, those arguing for a continuing role for NATO point to Russia’s incursion into Ukraine as evidence of renewed Russian power and its desire to recapture territory lost after the fall of the Soviet Union. Former Soviet states and now EU and NATO member states Latvia, Lithuania and Estonia all have borders with Russia. NATO has responded by expanding its European Response Force from 13,000 to 40,000 troops, creating a new ‘spearhead force’ of 5,000 troops and establishing new headquarters in its member states in the Baltic and eastern European regions. NATO hailed this as ‘the largest reinforcement of collective defence since the end of the Cold War’.

From a Russian perspective, in 2016, President Vladimir Putin claimed in his New Year address to the Russian people that NATO represented a key national security threat to the Russian Federation. Putin pointed to the ‘intensification of military activities, further expansion of the alliance and moving military infrastructure closer to Russia’s borders’ as evidence of the perceived threat.

It is clear that NATO–Russia relations are in a ‘sensitive period’. The tensions are a relevant example of the so-called security dilemma in global politics. The security dilemma reflects the fact that when one world power feels a threat from another, it increases its security defences, which in turn leads to the other power feeling a growing threat and increasing its own security defences accordingly. In the Cold War, this was seen most powerfully through the nuclear arms race between the Soviet Union and the USA. 

In December 2021 Vladimir Putin  said he will consider a military response if Russia feels threatened by Nato, and indicated that he is not ready to de-escalate tensions over a potential invasion of Ukraine.

 Putin –  demanded “security guarantees” from Nato – and told  his top military commanders that the west was to blame for the rising tensions. This came against a backdrop of a Russian buildup of tanks and artillery. The Russian president has railed against Nato enlargement since the fall of the Soviet Union and accused the west of turning Ukraine against Russia. After a revolution installed a pro-western government in 2014, Moscow annexed Crimea and sparked a conflict in east Ukraine that has left more than 14,000 dead. It has bristled at growing military cooperation between Ukraine and Nato countries.

“What the United States is doing in Ukraine is at our doorstep,” he said of Washington’s support for Kyiv. “And they should understand that we have nowhere further to retreat to. Under [US] protection, they are arming and urging on extremists from a neighbouring country at Russia. Against Crimea, for instance. Do they think we’ll just watch idly?”


Military operations

Despite being founded with the objective of countering the threat from the Soviet Union at the end of the Second World War, NATO’s first military operations did not take place until 1995. Humanitarian concerns primarily motivated two operations in the 1990s, both in former Yugoslavia:

■ In 1995, Operation Deliberate Force included air strikes against the Bosnian Serb army, which had carried out massacres in so-called UN safe zones, including in Srebrenica, where in July 1995 Bosnian Serb forces killed some 8,000 Bosnian Muslims. A UNSC Resolution had authorised this military operation, making this a good example of the UNSC using the forces of another international organisation (NATO) to carry out its objectives.

■ In 1999, NATO launched nearly 80 days of air strikes in Kosovo, in former Yugoslavia. Operation Allied Force was primarily a humanitarian mission to protect Kosovar Albanians from the armed forces of the Federal Yugoslav Republic and its leader Slobodan Miloševic. This operation was not backed by a UN Security Council Resolution, with Russia opposed and condemning the campaign as a breach of international law.

It is important to note that NATO’s first military operations came in a theatre of conflict and with objectives very different to those initially intended. Neither of these two campaigns in former Yugoslavia was carried out to protect a fellow NATO member state, as the collective security alliance intended. In the immediate aftermath of the Cold War, NATO focused on humanitarian crises within Europe and was able to do so both with and without the support of Russia.

Since NATO invoked Article 5 in 2001, the organisation’s operations have further expanded beyond their original geographical space, moving beyond Europe to the middle east and south Asia. Military operations in Afghanistan (2001–14) were conducted under NATO’s leadership. Similarly, the military no-fly zone and subsequent campaign of air strikes against Colonel Muammar Gaddafi’s regime in Libya in 2011 was a NATO-led operation.

NATO has also conducted counter-piracy operations in the Indian Ocean off the coast of Somalia, in order to protect international shipping lanes. These operations confirm that NATO is now a military alliance with its widest range of deployments, and indeed NATO has to some extent rebranded itself, by leaning towards a more humanitarian role in order to remain relevant. With a resurgent Russia, NATO is also rediscovering and redefining its role as a collective security alliance to counter Russian aggression.