For three quarters of a century our security has rested on two pillars: founding membership of NATO since 1949 and the bilateral defence agreement with the United States from 1951. The arrangement has served us well. We are an independent nation of 400,000 without an army, and we have gotten away with it. But beneath both pillars lay an unspoken assumption: that the United States would be a steadfast and unambiguous ally.
The world has been changing fast
Russia's invasion of Ukraine in 2022 set off the largest war in Europe since 1945. The conflict has also made itself felt beyond Ukraine's borders. Undersea cables and gas pipelines in the Baltic, for instance, have repeatedly been damaged under suspicious circumstances.
This concerns us directly. Nearly all of our communication with the outside world runs through fibre-optic cables on the ocean floor. Meanwhile, a military build-up is under way in the Arctic. Russia has rebuilt its Northern Fleet bases, and the waters between Greenland, Iceland and the United Kingdom — the GIUK gap — have once again become a key area in the defence of the Atlantic, just as in the Cold War.
Our closest ally has its eye on our neighbour
Then there is the second pillar. The President of the United States has repeatedly declared that the US needs to acquire Greenland, and has declined to rule out economic or even military pressure to that end. This pressure is being applied to Denmark, our NATO ally and one of our closest friends — and it concerns the country that is our nearest neighbour. In January 2026 it went as far as the United States threatening Denmark and other European countries with punitive tariffs over Greenland. The EU answered those threats as one, standing firmly behind Denmark.
A security guarantee that was once certain is now open to doubt. American leaders openly question their commitments to allies who "don't pay enough". Washington is reviewing how large a force the United States intends to keep in Europe.
Our Nordic neighbours have already responded. Finland and Sweden abandoned military neutrality — in Sweden's case more than two centuries old — and joined NATO in 2023 and 2024. Denmark scrapped its opt-out from EU defence cooperation in a 2022 referendum. The Nordic countries have also strengthened their resilience in many other ways, including by urging the public to prepare for the possibility of conflict — with Russia, for instance.
The EU is increasingly a security alliance
The EU was founded as a peace project, and it remains one. NATO is still the foundation of collective defence in Europe. But since 2022 the EU has taken bigger steps in security and defence than in the previous thirty years combined, in order to strengthen its members' security across a broad front, alongside NATO.
The EU Treaties contain a mutual assistance clause, Article 42(7): if a member state suffers armed aggression on its territory, the others are obliged to assist it by all means in their power. France invoked the clause after the 2015 Paris terrorist attacks, and every member state responded. A separate solidarity clause covers terrorism and disasters, whether natural or man-made.
Security today is about more than soldiers. It is about energy, cyber defence, supply chains, food, medicines, protection of critical infrastructure, and resistance to economic coercion. The EU has built tools for all of this. Among them is the Anti-Coercion Instrument, which lets the Union respond as one when a foreign power tries to bully an individual member state with tariffs or trade threats. A nation of 400,000 negotiating alone with a great power has almost no leverage. A market of 450 million does.
What membership would change — and what it wouldn't
Membership would not replace NATO, and it would not create an Icelandic army. The Treaties cannot oblige a member state to establish armed forces, as we explain in another card. The defence agreement with the United States would remain in force. The EU will not substitute for American military capability in the coming years; building European capacity takes time.
What membership would change is our own position. Today we often get behind the EU's foreign policy and measures after the decisions have been made, without having taken part in them. As a member we would sit at the table where Europe's foreign and security policy is shaped, with a veto, since such decisions require unanimity. The voice of small states carries more weight there than size alone would suggest. We would be inside the mutual assistance clause instead of standing outside it, and inside a powerful economic bloc that faces coercion united.
In short: Our security has rested on the goodwill of one great power on the other side of the Atlantic. That goodwill has become less certain at the very time the threats — to our undersea cables, to Arctic stability, to small economies under great-power pressure — are growing. EU membership would not replace NATO, but it would add a second anchor: 27 allies bound by treaty to come to our aid, and a seat at the table where decisions about our continent's security are made. In rough seas, you don't want to ride at a single anchor.
Sources and further reading:
- Article 42 of the Treaty on European Union — the mutual assistance clause (paragraph 7) and the explicit recognition that NATO remains the foundation of collective defence for its members.
- White Paper for European Defence — Readiness 2030 — the European Commission's March 2025 plan to mobilise up to €800 billion for European defence, including the €150 billion SAFE loan instrument.
- Reuters: Trump says US will get Greenland "one way or the other" — address to the US Congress, March 2025.
- Joint statement by the Presidents of the European Council and the European Commission on Greenland — 17 January 2026, at the height of US pressure on Denmark: "The EU stands in full solidarity with Denmark and the people of Greenland. Territorial integrity and sovereignty are fundamental principles of international law."
- Defense News: Pentagon has "kicked off" review of US force posture in Europe — formal review announced June–July 2026; some 5,000 troops already withdrawn from Germany.
- NATO launches Baltic Sentry to protect critical undersea infrastructure — standing NATO activity established in January 2025 after repeated damage to cables and pipelines in the Baltic Sea.
- EU–UK Security and Defence Partnership — agreed May 2025.
- Þjóðaröryggisstefna fyrir Ísland — Iceland's national security policy (parliamentary resolution, updated 2023) and the Foreign Ministry's overview of our defence arrangements, including the 1951 bilateral defence agreement.