(Photo by Pietro Naj-Oleari via Flickr/CC BY-NC-ND 2.0 DEED)
The decades-long partnership between the United States (U.S.) and European allies has come under threat since President Donald Trump took office in 2025. Relations across the Atlantic have particularly soured due to Trump’s recent threats to annex Greenland by any means necessary. The U.S. government has continued its attempts to seize the island despite Greenlanders being overwhelmingly against annexation. In a recent poll, only 6% of Greenlanders supported joining the U.S., while 85% opposed it.
Greenland, as part of the Kingdom of Denmark, is a member of the North Atlantic Treaty Organization (NATO), the U.S.-led military alliance and defence pact, alongside Canada and most European Union (EU) nations. NATO members collaborate significantly on military affairs, with the U.S. having a network of military bases across Europe that hold up to 100,000 troops, tanks, helicopters, missiles, and around 100 nuclear weapons. Legally, the U.S. is committed to defending other NATO nations if their territory is ever attacked under Article 5 of the NATO treaty.
Yet, experts have noted that Trump’s threats could lead to “the end of NATO.” Additionally , the U.S. is seeking to reduce its military presence in Europe. With the U.S.’s increasingly inconsistent and unreliable goals, the EU is seeking ways to diversify its reliance on U.S. military support. With this in mind, EU nations, alongside the United Kingdom, have reportedly been preparing to replace the U.S.’ role in European defence.
A European Army: What Would It Entail?
One idea to strengthen Europe’s military strength was recently brought to attention by Andrius Kubilius, the EU Defence Commissioner, who proposed that the EU should build a common army numbering 100,000 soldiers alongside the United Kingdom. This army would be built on top of the independent armies of each EU nation, rather than replacing existing national armies.
These calls echo those of other European leaders, such as Spanish Prime Minister Pedro Sánchez and Ukrainian President Volodymyr Zelenskyy. Polls have found majority support among civilians for building a common European army in around half of all EU countries, especially countries in Northern or Eastern Europe, closer to Russia.
Proponents of such a plan have argued that a European army would allow European nations to better defend their own territories. Sanchez, in particular, has noted that Europe needs to reduce its reliance on the U.S. so it is not living at the mercy of Russian or American leaders. Additionally, a common European army could mean a more rapid and unified European response to threats rather than having each country respond individually.
Opposing Foreign Policy Objectives Between EU Nations
Despite the benefits, building a European army will prove difficult. EU nations are already struggling to maintain unity in the face of Russia’s invasion of Ukraine. In particular, Hungary’s foreign policy objectives differ significantly from those of the EU, repeatedly blocking aid to Ukraine. Prime Minister Viktor Orbán has repeatedly denounced the EU, saying it does not respect Hungary’s sovereignty and claiming that the EU’s ultimate goal is to build a ruling bureaucracy ruling over participating states.
Similarly, Slovakia’s government has fought with the EU over aid to Ukraine, with Slovak Prime Minister Robert Fico claiming that he successfully defended national sovereignty and interests by vetoing sanctions against Russia. A European integration project, like building a common European army, would likely be opposed by both Hungary and Slovakia.
Even if not accounting for political reasons, there is disagreement among EU leadership on the best way to proceed. For example, the EU’s High Commissioner on Foreign Affairs, Kaja Kallas, has opposed a European army, stating instead that the EU should increase military spending and deepen integration among its national armies.
Fundamental Lack of Military Personnel
Along with the difference in foreign policy between EU members, the proposed European army still does not solve the fundamental issue behind the EU’s logistical problem: an army of 100,000 soldiers pales in comparison to the nearly 700,000 that Russia has deployed in Ukraine. Even without actual combat, the increased force is not a significant deterrent for potential attackers. At best, the proposed army would match the U.S.’ army in Europe. In total, all EU nations, plus the U.K., currently have around 1.5 million active personnel across their militaries.
Further, the potential collaboration does not address other military technology such as tanks, artillery, or defences. The proposal merely addresses military personnel. Adding more troops without any support further weakens the deterrence this European army may provide.
Still, in its current proposed form, the European army would add another layer of complexity to the EU’s military response. A new central army would be in addition to the armed forces of each EU nation, which have their own equipment, rules, and organizational structures. EU officials have noted that significant resources are currently being spent on coordinating the different EU armies, hindering collaboration. No clear vision has yet been put forward for this hypothetical European army, but the issue of leadership will need to be resolved to move forward.
Are There Other Options?
Besides building a European army, the EU is also exploring other options to strengthen its defences and become more self-reliant militarily. For instance, to increase the ability of European militaries to collaborate, the EU is focusing on harmonizing their armed forces as described in its “Future of European Defence” white paper.
This white paper highlights key areas for the EU to build capacity on, including military transportation, protection for key infrastructure, and electronic warfare. Through this, the EU has created a €150 billion loan fund that member states can borrow from in order to rapidly expand military production. The white paper also affirms the EU’s goal of having member states buy more equipment together. This inevitably increases the interoperability between different EU armies, meaning that they are better able to collaborate when using each others’ resources. Like, for example, when repairing equipment.
On this, the EU is investing more in domestic military production to reduce reliance on American military tech. The U.S. produces many of the weapons used by EU countries. Theoretically, the U.S. could prevent countries from using this equipment in a conflict by ceasing to sell spare parts or ammunition. This move also boosts the EU economy and strengthens the EU’s military production skill base.
What can the EU and other traditional NATO allies do?
Trump’s threats on NATO territory, such as Greenland and Canada, and by extension the alliance in general, have pushed the EU away from relying on the U.S. for defence. Building an additional European army on top of existing national armies is an option, but many challenges remain to be resolved before such a plan can succeed.
At its current scale, the proposed European army does not address compatibility between national armies and includes only troops, without considering military technology. It is a poor replacement for U.S. forces stationed in Europe should the need arise. Proponents of a European army also need to overcome internal EU opposition, particularly from Hungary and Slovakia.
Regardless of whether the EU decides to build a common army, the bloc should continue to increase interoperability and encourage domestic military production to improve Europe’s ability to defend itself, as the EU has already outlined in its recently proposed “Future of European Defence” paper.
Edited by Gabrielle Andrychuk
