Written by: Emilie Sterna

06 June 2025 

After World War II, Europe faced a high human cost, with 36.5 million Europeans dead,  including 19 million civilians. Daily life was marked by rationing and refugee camps. In this  context, on April 4, 1949, in Washington D.C., twelve countries (Belgium, Canada, Denmark,  France, Iceland, Italy, Luxembourg, the Netherlands, Norway, Portugal, the United Kingdom and  the United States) signed the North Atlantic Treaty, establishing the North Atlantic Treaty  Organization, better known as NATO. This alliance was created with three main objectives: to deter  Soviet expansionism, to prevent the revival of nationalist militarism in Europe through a strong  North American presence, and to encourage European political integration. Over the years, NATO  has expanded to 32 members today, in order to guarantee security in the North Atlantic area. The  organisation’s effectiveness relies heavily on Article 5, which states that “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 and consequently they agree that […] will assist the Party or Parties so attacked by  taking forthwith, individually and in concert with the other Parties, such action as it deems  necessary, including the use of armed force, […].” This article aims to dissuade other nations from  attacking any alliance member. However, recent events such as the re-election of Donald Trump in  the United States, who expressed scepticism toward NATO, the accession of Finland in 2023 and  Sweden in 2024, and the ongoing war between Russia and Ukraine, are reshaping the balance  within NATO and raising new questions about European security. This article aims to analyse the  internal challenges currently facing NATO, and the evolving European strategies for maintaining  their security, ahead of the upcoming NATO summit scheduled for June 24 and 25 in the  Netherlands.

The internal challenges facing the alliance : rising nationalism and disengagement of the  United States  

NATO is currently facing a number of internal challenges. With its next summit approaching  at the end of the month, the future of the alliance remains uncertain. The rise of nationalism in  Europe, coupled with the United States’ relative disengagement, is weakening the alliance’s  cohesion. Traditional support for NATO from the United States is decreasing, especially since the re-election of Donald Trump, as isolationism is gaining popularity. In fact, Donald Trump has already publicly challenged Article 5 of the North Atlantic Treaty, calling into question the  credibility of the United States’ commitment to its European allies. That is why the outcome of the  next summit is crucial for the organisation: it will either dismantle or rebuild the organisation itself.

First of all, Western countries are facing rising nationalism, as well as the weakening of  democracy. Western countries, fuelled by globalisation, growing inequalities, as well as the rise of  Chinese power and Russian aggression, are seeing their democracies weakened, with a rise in  populist and protectionist tendencies. For instance, in the United States, the pro-NATO consensus is  no longer current. Isolationism has become a priority among Republicans, who now hold an  unfavourable opinion of NATO. Moreover, although the rise of populism in Europe mainly  concerns unfavourable opinions on immigration and the European Union, it demonstrates a lack of  cohesion and collective spirit, leading to increased divisions within Europe. These reasons then  pose a threat to NATO’s credibility, as well as its existence. Without consensus and unity, member  countries risk falling into pronounced individualism. In other words, left-right polarisation within  member states diminishes the cohesion of the Alliance, and the differing focus of states on national  versus global interests makes consensus harder to achieve. Moreover, the era of globalisation in  which the world was unipolar, with the United States dominating as the only strong power on the  world stage, is over. Nowadays, the world stage is characterised by many influences. In this new  multipolar world, which tends to be more nuclear and unstable, NATO’s cohesion and actions  become more complicated to achieve. Indeed, with different influences, there are more and more  internal disagreements between the members of the alliance. They tend to act more according to  their own interests, thus the risk of fragmentation among members is increased. Consequently, the  rise of new powers such as China, Russia, and India, as well as the diversification of members’  interests, weakens NATO. Nevertheless, despite the difficulties it faces, NATO must continue to  promote democratic values and cooperate on defence and security issues, to solve common  problems, build mutual trust, and, in the long term, prevent conflicts.

However, the disengagement of the United States from NATO could have a huge impact on  the organisation. The embrace of an isolationist approach by the Trump administration has shifted  perspectives within political and military alliances. NATO has historically relied heavily on the  United States’ support. In fact, the United States has never wanted to let Europe take the lead in the  organisation, which is why NATO has remained highly dependent on American involvement. For

decades, the US has been hostile toward any form of European defense autonomy. Nevertheless, in recent years, the United States has accused European countries of not contributing enough to the  alliance’s budget and has urged other NATO members to increase their national forces and defense  spending. Trump has emphasised many times the burden that NATO places on the United States. He  has declared his intention to remove either a portion or all of the 80,000 US troops currently in  NATO’s permanent rotation in Europe, to decrease the budget allocated to the alliance (which is  currently around US$5 billion), and to reduce its security commitments to NATO. In fact, Trump  has called for a more equal balance of expenses within the alliance. He wants each country to  allocate at least 2.5% to 5% of its GDP to the defense budget, including a focus on enhancing  NATO’s capabilities. Trump even declared in 2024, before his presidential election, that Putin could  attack those who did not respect NATO’s financial obligations. Additionally, Minna Alander, a  defense analyst at Chatham House, says that under the Trump administration, the United States  sometimes seemed to support Russian objectives. For instance, Trump praised Putin, negotiated  with Russia excluding Ukraine and Europe, attacked Ukrainian President Zelensky, and repeated  Russian lies about the origins of the war. The credibility of the American commitment is therefore  even more questioned with Trump’s recent statements. These recent declarations raise an important  question about US involvement in the alliance, especially its full involvement in the case of the  invocation of Article 5. Indeed, even though the United States traditionally provides the most  support, a simple technical support could fulfil the conditions of Article 5. However, currently the  United States provides about 70% of NATO’s military capabilities, more than 100,000 soldiers in  Europe, as well as nuclear capabilities, intelligence, logistics, and reconnaissance. Moreover,  NATO’s command in Europe is still led by an American. At the moment, no European country can  replace the role of the United States due to a lack of comparable military and financial means.

If the United States leaves the alliance or significantly reduces its involvement, the only  option left for NATO is to focus more on Europe. European countries must demonstrate that the  alliance remains alive even without strong participation from the United States. Therefore, to ensure  their security, especially in the context of Russia’s threats, European countries need to implement  new strategies.

European strategies to guarantee their security 

The rise of populism, the weakening of democracies, and the gradual withdrawal of the United States threaten the future of NATO. To survive, European members must become more autonomous, responsible, and militarily strong, at the risk of seeing the Alliance disappear. To  ensure its future, NATO must undergo significant transformations and changes. First, stabilising  regions around Europe such as the Balkans, the Mediterranean, and the Caucasus is necessary to  avoid others crises. Second, faced with the rise of authoritarian regimes, Europe can no longer  afford to be only a civilian power but must also present itself as a military power to ensure its  security. That is why rearmament and new military investments are necessary, especially in case the  United States leaves NATO. The European Union must be able to finance its defence independently.  This transformation is even more necessary since the Russian aggression against Ukraine in  February 2022. Indeed, during the Cold War, the asymmetry within the alliance between the United  States and Europe was a choice. However, today, European weakness is pushing the United States  to withdraw. Already under Joe Biden, the American security priority has shifted to the Indo-Pacific  region, due to rivalry with China, to the detriment of Europe. Therefore, this shift motivates  European members to fortify their own defence. As an example, the new German chancellor,  Friedrich Merz, declared that his goal is to achieve independence from the United States in terms of  security. He even wondered if the alliance leaders’ meeting in June would still be about NATO in its  current form or if the creation of an independent European defence capability should be accelerated.  Merz will then join the trio of major European powers, with the United Kingdom and France.  Greece, Norway, and others express their concerns, while Denmark has announced a strong increase  in its defence spending. The United Kingdom has also announced an increase in its military budget,  reducing foreign aid to finance an additional 13 billion pounds per year. Nevertheless, the massive  aid to Ukraine has depleted military stocks. That is why, currently, NATO is still relying heavily on  the United States’ capabilities, both in terms of materiel and forces. NATO needs to establish a clear  plan to avoid breaking Europe apart, which Moscow could take advantage of.

Yet replacing the US role in NATO is very difficult. Here are some examples: France, even  though it has the most advanced military capacity in the European Union, an independent nuclear  arsenal, and global expeditionary forces, cannot replace the United States within NATO due to a  lack of human resources and budget. Turkey, which has the second-largest army in NATO, a  growing defense industry, and solid regional experience, has little chance of replacing the United  States, as its priorities are focused on the Eastern Mediterranean, the Middle East, and its immediate  neighbourhood. Moreover, its relations with other NATO members such as Greece or France are  complex and difficult. Germany, despite promises to increase the military budget after the invasion of Ukraine, still faces structural problems and a pacifist tradition; the German army is also not able to fill the void left by the United States. Regarding Eastern Europe, the American withdrawal would  be a major problem as they rely on American military means to deter Russia from continuing its  expansion. To counter this, Poland has already planned a massive increase in its military spending. Therefore, NATO must strengthen its defence and deterrence, an urgent task since the annexation of  Crimea in 2014 and the invasion of Ukraine in 2022. In June 2022, the alliance established a new  force model and a rapid reaction force to overcome European disarmament. In addition, NATO’s  expansion to include Finland and Sweden has strengthened security in the Baltic Sea region.  Nevertheless, It’s still difficult to get forces ready and send them where needed in Europe, the  situation in Ukraine remains the Alliance’s top strategic concern and will determine its future in  Europe.

NATO must work in several fronts to strengthen its deterrence and defence. The European  Union (EU) must become a strategic actor in defence alongside NATO to fill the gaps that the  alliance cannot cover, especially on cross-border and logistical issues. Europe faces enormous  logistical challenges. The EU must then accelerate infrastructure upgrades, expand military  transport capabilities, and establish a “military Schengen” to facilitate the movement of troops and  equipment. Moreover, the war in Ukraine has revealed the weaknesses of the European defence  industry: insufficient weapon stocks, fragmentation of national interests, and inability to innovate  globally. To remedy this, the EU must encourage joint production and acquisition of military  equipment and supplies. The EU must also strengthen its capacity to plan and execute defence  actions while remaining aligned with NATO’s objectives. Better coordination between NATO and  the EU is essential to avoid duplication. The goal is to build a stronger European pillar within  NATO, where the EU assumes an increased share of the defence burden. This involves modernising  infrastructure, reforming the defence industry, and improving cooperation between NATO and the  EU. This approach aims to send a clear message to adversaries: Europe and NATO do not retreat:  they strengthen and remain united in the face of strategic challenges.

In conclusion, a Europe-focused approach for NATO is seen by some as a promising way to  rebuild a more sustainable future for the alliance, while others argue that without American  resources, NATO would gradually weaken, potentially creating an opening for Russia to intensify  its aggression against Eastern European countries. However, it is crucial to emphasise that the  possible dissolution or weakening of the alliance could pose significant risks and consequences for both European countries and the United States. Despite internal challenges and shifting power dynamics, NATO remains a vital structure that provides essential security cooperation. It is in this  context that NATO leaders will gather in the Netherlands for the upcoming summit on June 24 and  25, where critical discussions on the alliance’s future and Europe’s evolving role in collective  security are set to take center stage.

References:

Bazin, A. And Kunertova, D. (2018). An Alliance Divided? Five Factors That Could Fracture  NATO. Army University Press, Military Review, January-February 2018. https:// www.armyupress.army.mil/Journals/Military-Review/English-Edition-Archives/January February-2018/An-Alliance-Divided-Five-Factors-That-Could-Fracture-NATO/

Budginaite-Froehly, J. (2025, March 5). The EU must become a strategic player in defense— alongside NATO. Atlantic Council. https://www.atlanticcouncil.org/in-depth-research-reports/issue brief/the-eu-must-become-a-strategic-player-in-defense-alongside-nato/

Charron, A. (2021, January). Structural Challenges Facing NATO to 2040. Canadian Global Affairs  Institute. https://www.cgai.ca/structural_challenges_facing_nato_to_2040

FitzGerald, J. (2024, February 11). Trump says he would ‘encourage’ Russia to attack Nato allies  who do not pay their bills. BBC. https://www.bbc.com/news/world-us-canada-68266447

Hadfield, A. (2025, May 30). NATO faces make-or-break decision on a post-US future. Asia Times.  https://asiatimes.com/2025/05/nato-faces-make-or-break-decision-on-a-post-us-future/#

Mao, F. (2025, February 26). Can Europe still count on the US coming to its defence? BBC. https:// www.bbc.com/news/articles/c0l1w1w41xzo

NATO. (n.d.). The signing ceremony. https://www.nato.int/cps/en/natohq/declassified_137799.htm NATO. (n.d.). What is NATO? https://www.nato.int/nato-welcome/index.html

NATO. (n.d.). NATO summits. https://www.nato.int/cps/en/natohq/topics_50115.htm?selectedLocale=en

Schneider, H. (2025, May 2). The decline of globalization and the future of NATO. Geopolitical  Intelligence Services (GIS). https://www.gisreportsonline.com/r/globalization-nato/