Europe's Sovereignty Imperative: B9 Summit, Record Spending, and the New Architecture of European Defence

On Wednesday 13 May 2026, Romanian President Nicușor Dan and Polish President Karol Nawrocki will co-chair the Bucharest Nine (B9) Summit at Cotroceni Palace under the theme "Delivering More for Transatlantic Security." NATO Secretary General Mark Rutte and Ukrainian President Volodymyr Zelensky will attend alongside the presidents of Lithuania, Estonia, the Czech Republic, Latvia, Slovakia, and Finland, with Denmark's Prime Minister Mette Frederiksen, Sweden's defence minister, Norway's foreign minister, and US Under Secretary of State for Arms Control and International Security Thomas DiNanno also present. The guest list tells its own story: the security architecture of Europe has expanded dramatically since the B9 format was conceived in 2015 by Romania and Poland following Russia's annexation of Crimea, and the inclusion of Nordic countries since 2025 reflects a continent where neutrality is no longer a viable strategic posture.

The summit convenes at a moment of extraordinary convergence for European defence. The Stockholm International Peace Research Institute (SIPRI) reported on 27 April that global military expenditure reached a record $2.89 trillion in 2025, marking the eleventh consecutive year of increase. Europe was the primary driver, with spending surging 14 percent to $864 billion. Global military spending as a share of GDP climbed to 2.5 percent, its highest level since 2009. Within Europe, Germany's expenditure rose 24 percent to $114 billion, surpassing NATO's 2 percent GDP guideline for the first time since reunification in 1990, reaching 2.3 percent. Spain's spending jumped 50 percent to $40.2 billion, crossing the 2 percent threshold for the first time since the target was agreed in 1994. These are not marginal adjustments; they represent a structural reorientation of European fiscal priorities at a scale not seen since the end of the Cold War.

The political catalyst for this transformation is well understood. The Trump administration's persistent questioning of NATO's mutual defence guarantee, combined with the grinding attrition of Russia's war in Ukraine, has forced European capitals to confront an uncomfortable reality: the transatlantic security bargain that underwrote European prosperity for eight decades can no longer be taken as a permanent feature of the international order. At the NATO Summit in The Hague in June 2025, allies agreed on a new long-term benchmark of at least 3.5 percent of GDP for core defence spending, with a stretch objective of 5 percent from which Spain formally opted out. McKinsey's European Defense Dashboard, updated April 2026, projects that accounting for fiscal capacity, European NATO defence spending could reach €800 billion by the end of the decade. The European Union's Security Action for Europe (SAFE) programme has been structured to mobilise up to $178 billion for continental defence upgrades. These are no longer aspirational figures discussed at academic conferences; they are budget lines being executed in real time.

The second major axis of transformation is the pursuit of defence sovereignty — the drive to reduce reliance on American weapons manufacturers and supply chains. The Guardian reported on 10 May that a crop of well-funded European defence technology startups is gaining momentum, buoyed by billions in new government contracts. German company Helsing, backed by Spotify founder Daniel Ek, and the drone makers Quantum Systems and Stark Defence have won orders from Germany's military for attack drones. Portugal's Tekever reached a billion-dollar "unicorn" valuation with 1,200 employees and new factories in Swindon, UK, and Cahors, France. The British missile maker Cambridge Aerospace is reportedly approaching the same threshold. In a small workshop in England's East Midlands, startup Skycutter is using 3D printers to manufacture fuselages for interceptor drones, with partner factories in Ukraine producing hundreds of thousands of units monthly. Gen Sir Roly Walker, the UK's Chief of the General Staff, captured the doctrinal shift when he set a target for British forces' equipment to be 20 percent "survivable" (crewed), 40 percent "attritable" (acceptable to lose), and 40 percent "consumable" (single-use). This represents a fundamental break from the platform-centric procurement philosophy that dominated NATO militaries for generations.

The financial markets have registered the shift with remarkable velocity. Rheinmetall, Germany's 137-year-old defence manufacturer, saw its shares climb 154 percent in 2025, while ThyssenKrupp gained 215 percent. South Korea's Hanwha Aerospace surged 193 percent, building on a 154 percent gain in 2024, driven in part by European demand for the K9 self-propelled howitzer. BAE Systems rose 49.2 percent. This investor enthusiasm is sustained by concrete policy machinery: Berlin's historic debt reform in March 2025 unlocked constitutional constraints on defence borrowing, and the EU's €800 billion mobilisation framework has provided a demand signal that defence-industrial boards across the continent are now scaling to meet.

Yet significant structural tensions persist beneath the surface. The B9 Summit itself embodies a persistent asymmetry: the frontline states of NATO's eastern flank — Poland, the Baltic republics, Romania — have consistently outpaced western European allies in defence spending as a share of GDP, yet their exposure to Russian military power remains disproportionately acute. GLOBSEC's 2026 assessment of battle readiness across ten Eastern Flank states found progress to be real but uneven, with critical gaps in mobilisation speed, logistics infrastructure, and industrial capacity. The Chatham House analysis published this month on Germany's rearmament trajectory captured the paradox of scale without doctrine: Germany's fiscal capacity, industrial base, and geographic centrality make it an unavoidable player in any coherent European defence architecture, yet "rearmament without doctrine risks strategic incoherence." The question of who commands, under what rules of engagement, and with what political mandate remains unresolved.

The UK-EU dimension adds further complexity. The Security and Defence Partnership signed on 19 May 2025 established a formal framework for cooperation, and Armed Forces Minister Luke Pollard confirmed this month that implementation discussions are underway covering Iran, Russia's war in Ukraine, and irregular migration. Yet the UK has been explicit that its engagement with EU defence structures remains subordinate to a "NATO First" policy, and the collapse of talks for Britain to join the SAFE fund underscores the persistent political sensitivity of any arrangement that could be portrayed in Westminster as ceding sovereignty to Brussels. The European Council on Foreign Relations has identified six key issues that London and Brussels must resolve for the pact to realise its potential, spanning industrial participation, operational coordination, and political oversight.

What emerges from this picture is a Europe in the midst of the most rapid and consequential defence build-up since the late 1940s, but one where the institutional, doctrinal, and political frameworks have not yet caught up with the scale of the fiscal commitment. The B9 Summit in Bucharest represents another incremental step toward coherence, bringing together the states with the greatest stake in a credible eastern deterrent alongside the NATO leadership that must translate national spending surges into collective capability. Whether the architecture that emerges will be genuinely European, durably transatlantic, or a patchwork of bilateral arrangements that falls short of strategic coherence remains the defining question of European security in 2026 — and the answer will be shaped by summits like the one convening in Bucharest today.