NATO | Towards a more European alliance
European member states of NATO are preparing to take on a larger share of the alliance's conventional defence burden amid signals of reduced US commitment to European security.
The US Department of Defense has stated that the United States will no longer serve as the "primary guarantor" of European security, while the US Ambassador to NATO has said Europe is expected to "take over the conventional defence of the European continent."
Mixed signals from different arms of the US administration — reduced military commitment on one hand, continued arms sales encouragement on the other — have created uncertainty within the alliance.
European members are responding by discussing a stronger "European pillar" within NATO and parallel EU-level defence structures, while debating whether this complements or dilutes the alliance's unified command.
NATO and Article 5 — Collective Defence (Washington Treaty, 1949)
NATO was established by the North Atlantic Treaty (Washington Treaty), signed on 4 April 1949 by 12 founding members. Article 5 is the treaty's cornerstone: an armed attack against one member is treated as an attack against all, obliging other members to assist, "including the use of armed force." Article 4, distinct from Article 5, allows any member to request consultations when it believes its security is threatened, without triggering collective defence obligations.
Key Details
- Article 5 has been formally invoked only once — on 12 September 2001, a day after the 9/11 attacks on the United States.
- NATO headquarters is in Brussels, Belgium; the Supreme Allied Commander Europe (SACEUR), NATO's top military commander, has by convention always been a US general.
- Membership has grown from 12 founding states (1949) to 32 today, with Finland (2023) and Sweden (2024) the most recent entrants following Russia's invasion of Ukraine.
The debate over a "more European alliance" concerns who bears the operational and financial weight of Article 5 commitments — the current push is for European militaries, not the US, to shoulder conventional defence of the continent.
NATO Defence-Spending Benchmarks — From 2% (Wales, 2014) to 5% (The Hague, 2025)
NATO's defence-spending guideline has been the central metric of "burden-sharing" debates. At the 2014 Wales Summit, held after Russia's annexation of Crimea, members pledged to move towards spending at least 2% of GDP on defence by 2024, with 20% of that on major equipment and R&D. At the 2025 Hague Summit, allies agreed to a new, higher target.
Key Details
- Hague Summit (June 2025): members committed to 5% of GDP annually on defence and security by 2035 — split into 3.5% for core defence requirements (meeting NATO Capability Targets) and 1.5% for broader resilience, critical infrastructure protection, and defence-industrial capacity.
- The 2% (Wales) target was a guideline, not a binding treaty obligation, and many members missed it for years.
- The sharp jump from 2% to 5% within roughly a decade reflects both the Russia-Ukraine war and pressure from the current US administration for reduced US financial exposure.
The 5% Hague commitment is the concrete financial expression of Europe "playing a larger role" — it is the mechanism through which European members are expected to fund the shift away from US-centric defence.
European Strategic Autonomy — PESCO and the EU Defence Architecture
Distinct from NATO, the European Union has built its own defence-cooperation structures, raising the recurring question of whether EU defence integration complements or competes with NATO. Permanent Structured Cooperation (PESCO), launched in December 2017 under the EU's Common Security and Defence Policy, allows willing member states to jointly develop defence capabilities and invest in shared projects, coordinated with the European Defence Fund.
Key Details
- PESCO currently includes the vast majority of EU member states in binding commitments to increase defence spending and collaborative capability development.
- The European Defence Fund co-finances joint defence research and capability projects across the EU.
- Tension exists between "European pillar within NATO" (strengthening the alliance's European half) and "EU strategic autonomy" (building independent EU capacity) — the former keeps the US-led command structure intact, the latter risks duplicating it.
The alliance's internal debate is precisely over which of these two models — a stronger European component inside NATO, versus separate EU structures — should absorb the responsibility the US is stepping back from.
- NATO founded: 4 April 1949, Washington Treaty, 12 founding members; now 32 members.
- Article 5 invoked once: 12 September 2001 (post-9/11).
- Wales Summit (2014): 2% of GDP defence-spending guideline, target year 2024.
- Hague Summit (June 2025): 5% of GDP by 2035 (3.5% core defence + 1.5% broader security/resilience spending).
- PESCO launched: December 2017, under the EU's Common Security and Defence Policy.
- Most recent NATO enlargements: Finland (2023), Sweden (2024).