Debating Matters Transatlantic
INTRODUCTION
The North Atlantic Treaty Organisation (NATO) is an intergovernmental military alliance of North American and European powers committed to the principle of common defence. It was founded in 1949, following the end of World War II, amid growing suspicions about the Soviet Union’s geopolitical intentions in Western Europe [Ref: NATO]. NATO had 12 founding members and has since expanded to 32 member states across North America and Europe, with the latest accession countries being Finland and Sweden. Importantly, only three member states – the USA, Canada and Turkey – are outside of Europe, making the composition of NATO predominantly European.
The fundamental goal of NATO is to safeguard the freedom and security of its members through a military alliance, primarily acting as a system of collective defence [Ref: NATO]. Article 5 of the North Atlantic Treaty is the cornerstone of this: it establishes the principle that an armed attack against one member is considered an attack against all members [Ref: NATO].
NATO also has a broad network of programs to handle threats that are below the threshold of Article 5, primarily through structured partnerships and out-of-area operations. These partnership networks pursue dialogue and practical cooperation on a wide range of political and security-related issues, including global challenges like terrorism, civil emergencies and cyber-attacks [Ref: NATO]. These programs protect the Euro-Atlantic region by projecting stability and establishing critical defence networks to deter threats before the need to invoke Article 5.
The debate on NATO’s role in global security centres around two competing views. Those in favour of NATO argue that it has a clear track record of proven deterrence effect, particularly through access to US capabilities, including intelligence and mutually assured destruction via its nuclear stockpiles. In this view, NATO remains vital because it continues to fulfil these same core functions: keeping America engaged in European defence, deterring Russian aggression, and integrating powerful European states within a stable collective security framework.
Critics of NATO argue that the alliance is no longer the most effective means to ensure global security. Some argue that the encouragement of European dependence on the United States has left their militaries underdeveloped and its security dependent on American support. This dependence is argued to have limited Europe’s geopolitical autonomy, leaving European states vulnerable to shifts in US leadership and foreign policy. This problem is exacerbated by questions over whether the US and Europe have the same security priorities; the recent war between America and Iran, without the support of NATO, suggested to some that the interests of European states and America are now diverging. Others also argue that NATO’s potential expansion could risk threatening Russia, putting Europe and its allies at risk.
And as NATO expands, does it strengthen its ability to provide collective defence or does it weaken the alliance? Concerns have arisen since the accession of Finland and Sweden into the alliance, as people wonder whether 32 nations can even agree on foreign policy and move in one direction. So, as NATO expands, does the expansion create a risk of fragmentation, and what other potential challenges can arise when dealing with how this expansion changes perceptions of the alliance to outside states?
DEBATE IN CONTEXT
Historical relationship and alliance
The American-European relationship has historically been categorised as an ‘indispensable partnership’ that is rooted in shared democratic values, free-market capitalism and mutual security. Within this broader transatlantic alliance, the UK-US relationship has often been described as a ‘special relationship’, reflecting the two countries’ shared language and historical ties, as well as their close diplomatic, military, intelligence and economic cooperation.
Supporters of NATO argue that the war in Ukraine and the increasing strength of the powers along the ‘Axis of Aggressors’ (China, Russia, North Korea and Iran) [Ref: FDD] give ever-increasing necessity to NATO, as it still remains a key symbol and body for countering the threats of communist or authoritarian governments. They argue that the increasing economic power of these states necessitates an allied approach in order to demonstrate a united front and develop the amount of technologically sophisticated weaponry and technology to counter this changing threat [Ref: Radio Free Europe / Radio Liberty].
Despite the alliance existing for over 75 years, Article 5 has only ever been invoked once as a response to the terror attacks against America on 9/11. This led NATO forces to support America in their war against Afghanistan from 2001-2020. Some argue that this demonstrated the value of the alliance, despite the much smaller size and capability of the European commands; the fact that the allied forces stepped in highlighted a key commitment to collective defence and reinvigorated belief in the strength of the partnership in the face of emerging threats [Ref: Wilson Center].
However, since the close Blair-Bush relationship of the early 2000s, the transatlantic relationship has faced periods of increasing strain. During the Brexit campaign, President Obama warned that the UK would be at the ‘back of the queue’ for a US trade deal if it left the European Union. More recently, tariffs imposed under President Trump have placed further pressure on US-European relations, disrupting decades of relatively predictable trade cooperation and raising questions about the long-term stability of the transatlantic partnership. [Ref: LSE]. Some argue that the mistrust created, coupled with Trump’s repeated dismissal of NATO – as a ‘paper tiger’, that is ‘obsolete’ and ‘costing a fortune’ for the US – has damaged the foundational relationships within NATO [Ref: BBC]. However, there remain many Americans support the commitment to NATO for various diplomatic, military and economic reasons, believing that a long-term partnership demonstrating a commitment to collective defence improves their security.
This matters because the United States is indispensable to NATO, contributing roughly 70 per cent of the alliance’s overall militarycapability and serving as its strategic backbone. This heavy reliance means that President Trump’s threats to withdraw from NATO or cut US support have caused significant concern among allies, potentially threatening NATO’s effectiveness and Europe’s security [Ref: CSIS]. The subsequent panic among allied leaders has led to an increase in defence budgets after criticism that each member state was failing to contribute two per cent of its GDP – the previous requirement for member states. What was viewed as a post-Cold War ‘peace dividend’ by European countries is viewed by their critics as outsourcing their defence spending to the US to pay for generous welfare programs. Thus, even with the alliance there are concerns that the failure of European states to fulfill their commitment to defence has left the Western allies more vulnerable to future threats as they have not produced the personnel, missiles or technology that would be needed in the case of an attack.
Security Risks of Article 5
Article 5 has only been invoked once: after the terrorist attacks of 9/11 on US soil, leading to NATO’s involvement in Afghanistan. Many member states, including the UK, France, Canada, and others, contributed thousands of troops to support the US, though states were not automatically required to participate militarily.
As American foreign policy focuses on the Indo-Pacific, if the US became involved in a conflict with China over Taiwan, European NATO members could face pressure to provide support, through either resources, military assistance or personnel, while simultaneously confronting Russia closer to home. This highlights a fundamental concern with NATO (the same critique Charles de Gaulle had when he pulled France out of NATO in 1967): that collective defence could draw states into conflicts that do not directly serve their national interests.
Similarly, critics argue that NATO’s expansion towards Russia increases the risk that existing members could become involved in conflicts arising along historically contested borders, suggesting that the expansion of NATO could threaten global security as it becomes viewed as a growing threat by states outside of the alliance.
Throughout the discussion on European security, it is clear that there is a need to increase defence investments and strengthen allied relationships, but which pathway is the most vital for global security? Is Europe capable of securing itself? Or is NATO still foundational to Western security frameworks? Do the benefits outweigh the risks?
Geographical relevance and the Russian attack
Since Russia’s attack on Ukraine in 2022, European states have increased their defence spending. Moreover, debates over the expansion of NATO into Eastern European states, including the expansion of Finland and Sweden in 2024, highlights that the axis between Europe and Russia is a key concern for the security of all Western countries.
Russia’s invasion of Ukraine in 2022 has offered NATO a renewed sense of purpose in a common enemy [Ref: Atlantic Forum]. The united support for Ukraine has shown a demand for NATO to act as a protector of Europe, with Ukraine desperate for full membership of NATO, and Finland and Sweden joining the alliance [Ref: Chatham House]. This highlights NATO as an organisation European states are desperate to be part of for their security.
However, European states face very different security threats. For Finland, which shares a long border with Russia, NATO membership and greater defence spending are clearly important. But the same calculation may not apply to countries such as Spain or Italy, which are geographically removed from Russia and face different domestic and security priorities. Spain, for example, resisted NATO’s five per cent spending target in 2025, arguing that it could meet its required military capabilities while spending only 2.1 per cent of GDP. Is NATO vital for Spanish security?
Moreover, critics of NATO argue that the existence of NATO has done more harm than good to global security. While it is argued that NATO has been the ‘only thing that has prevented Vladimir Putin from conquering three democratic countries that were former Soviet Republics’ [Ref: University of Rochester], it has also been seen to increase tension as American forces get closer to the Russian border. Some argue that Putin’s actions in Ukraine were due to the increased sense of encirclement he felt at the expansion of NATO forces across the Russian border. George Kennan in 1997 warned that NATO expansion ‘would be the most fateful error of American policy in the entire post-Cold War era’ [Ref: Australian Institute of International Affairs].
However, despite disagreements over funding and the allocation of resources within the alliance, supporters maintain that to dissolve the pact completely would have a detrimental impact on global security. It would signal to adversaries that America is unable and unwilling to defend or assist the West, giving opponents an easy way to expand their power. With the changing nature of warfare, this may not be purely military but also through cyber-attacks and economic sanctions.
NATO today
Critics of NATO question its contemporary relevance to global security, arguing that the changing world has eroded its united front. The recent erosion of trust between the US and Europe can be traced to three geopolitical events: the dispute over Greenland, the war in Iran, and the tariffs imposed by the US on European allies. Many ‘realist’ defence theorists argue the US is engaged in great-power competition with China. Thus, spending resources to guard Europe against a Russian state – which has less manpower, a far smaller economy and lower industrial capabilities than Europe – is a misallocation of resources in their view. Instead, there should be a greater focus on the rise of technological warfare, pivoted towards East Asia.
In 2023, the US Congress voted to prohibit the president from unilaterally withdrawing from NATO without the approval of a two-thirds Senate majority or an act of Congress [Ref: BBC]. While this is significant for the stability of NATO, the rhetoric presented by Trump highlights the doubt over the future of NATO, pushing European countries to seriously consider their security alliances and frameworks.
The fragmentation of the alliance due to changing threats and cyber-warfare can be seen in the recent rise in cyber-attacks from Russia, China, North Korea and Iran against the UK. MI5, the UK’s domestic counter-intelligence and security agency, has increased its assessment of the threat of terrorist attack on the UK to ‘severe’ due to these states’ role in spreading misinformation and radicalisation [Ref: CyberNews]. The UK has subsequently enacted and updated legislation to defend against these foreign attacks. But as these security threats have not warranted a specific conversation or response from NATO, does this suggest that it is less equipped to actively respond to the new age of information warfare?
But as new technologies have changed expectations and understanding of warfare, Article 5 has been expanded to acknowledge that cyber-attacks could lead to the invocation of collective defence: ‘cyber-attacks can reach a threshold that threatens national and Euro-Atlantic prosperity, security and stability’ [Ref: NATO]. This can cause as much damage to nations and civilians as a conventional military attack. While some might argue that this risks a more insecure geopolitical environment, supporters of NATO highlight that its crucial work in collaborating and combining expertise in new technological warfare has strengthened security. Cyber-attacks remain more covert and difficult to assess, so while NATO has not consolidated its ability to deal with these threats, new emerging frameworks suggest it could be crucial for European states to effectively adapt to changing warfare.
NATO 3.0 has emerged as a bid for a revival of the alliance. By focusing on a ‘stronger Europe in a stronger NATO’, NATO’s secretary general, Mark Rutte, seeks to maintain NATO’s role in collective defence while shifting the focus onto European defence rather than a reliance on the shelter provided by the US defence umbrella [Ref: RUSI]. At the same time, Rutte is desperate to maintain US commitment to NATO, declaring to President Trump after the crisis in Iran that ‘Donald, you have driven us to a really, really important moment for America and Europe, and the world. You will achieve something NO American president in decades could get done.’ [Ref: CBC]
While the debates on NATO funding are essential for the longevity of the organisation, American politicians’ criticism of the alliance has undermined the perception of NATO as a unified and dependable force. This has prompted a broader reassessment of NATO’s role and whether it remains the most effective means of safeguarding Europe’s security. However, NATO remains a key symbol of the collective power and defence of Western liberal democracies against rogue states and acts of aggression; many argue that without this alliance there would have been much greater threats to allied states. Moreover, as technology and warfare change, NATO forces are changing their priorities to combine knowledge, expertise and resources to improve their responses to cyber warfare and drone attacks. Some contend that this points to NATO’s important role in global security, while the nature of its forces may evolve to address the changing threats. Others argue that NATO is no longer the best way to achieve such aims.
KEY TERMS
Global security: the collective effort of nations, international organisations and global bodies to ensure worldwide peace, stability and survival, and to address threats that transcend borders.
Collective security: the international political arrangement in which states agree that an act of aggression against one member is treated as an aggression against all, requiring a unified response, creating a deterrent to war.
National security: a sovereign state’s ability to protect its citizens, economy, institutions and core values from external and internal threats.
Article 5: states that an armed attack against one NATO member shall be considered an attack against them all.
The Partnership for Peace (PfP): a programme of bilateral cooperation between individual Euro-Atlantic partner countries and NATO.
ESSENTIAL READING
Europe’s secret Plan B to replace NATO
The Economist 19 May 2026
To Ensure Its Security, Europe Needs a Stronger Hand in NATO
German Council on Foreign Relations 4 February 2026
Trump interview: I am strongly considering pulling out of NATO
Telegraph 1 April 2026
FOR
Trump’s plan for NATO 3.0
UnHerd 11 July 2026
Five reasons why Ukraine should be invited to join NATO
Atlantic Council 11 July 2024
Finland brings great value to NATO’s future deterrence
Chatham House 20 April 2023
Strengthening NATO’s eastern flank
NATO 17 June 2026
What Finland and Sweden Bring to NATO
CEPA 18 December 2024
Finland in NATO: Bolstering Arctic Defense & Baltic Stability
Institute for Youth in Policy 20 July 2023
AGAINST
NATO is becoming irrelevant and Europe is totally unprepared for it
Brussels Signal 20 March 2026
Two Years in NATO, Finland is Searching for a Plan B
RUSI 17 March 2025
NATO: The Most Dangerous Organisation on Earth
The Tricontinental 10 June 2025
The decline of the West and the rise of ‘the Rest’ will lead to a new world order
Chatham House 16 December 2025
As NATO strains deepen, Finland faces a new security dilemma
Jerusalem Post 3 May 2026
Tensions between the US and Europe loom large over NATO summit
Chatham House 6 July 2026
BACKGROUND
The Addition of NATO Members Over Time (1949-2024)
University of Notre Dame 23 March 2023
NATO member countries
NATO 11 March 2024
Reacting to a geopolitical setback: NATO expansion in Sweden and Finland through the lens of Russian geopolitical culture
Matthew Blackburn European Journal of International Security 29 July 2026
Europe’s little-known mutual defence clause: Is it a NATO substitute?
Aljazeera 30 April 2026
NATO, European Spending and US Grievances
CATO Institute 12 May 2015
Study on NATO Enlargement
NATO 3 September 1995
The Return of Protectionism: Trump’s 2025 Tariffs and the Shifting Landscape of Global Trade
LSE Public Policy Review 13 May 2026
War Department Review to Ensure ‘NATO 3.0’ Becomes Europe-Led Defense Alliance
US Department of War 18 June 2026
The Importance of the Expansion of NATO: What Can This Do to Increase Security Around the Alliance?
Atlantic Forum 6 July 2023
IN THE NEWS
What do Trump’s latest comments on leaving Nato mean for the alliance?
BBC 1 April 2026
U.S. Strikes Iran and Blocks Its Oil Sales
New York Times 7 July 2026
NATO defence push already strains Europe’s budgets
Reuters 6 July 2026
Many Nato countries not spending enough to support Ukraine, says Rutte
Guardian 21 May 2026
Rutte tells Sky News US is ‘completely committed to NATO’ – but Trump has one expectation
Sky News 8 July 2026
US to cut air and naval assets deployed for NATO operations in Europe
Aljazeera 12 June 2026
London, Washington coordinate military, diplomatic plans for Strait of Hormuz: Starmer
The Cradle 10 April 2026
Leaders gather in Hague as Nato chief Rutte says higher spending top priority
BBC 25 June 2025
Secretary General reaffirms transatlantic unity in Warsaw: There is no alternative to NATO
NATO 26 March 2025
NATO 3.0 to Emerge at Ankara Summit Amid Fragile Unity
RUSI 6 July 2026
Trump renews call for US to take over Greenland as he arrives for Nato summit
Guardian 7 July 2026
Grabbing Greenland: Impact on NATO and the EU
The International Centre for Defence and Security 19 January 2026
US allies apprehensive after capricious Trump changes tune at Nato summit
Guardian 12 July 2026
NATO Is Still a Sick Puppy
Foreign Policy 13 July 2026