A Window of Opportunity or a Window of Vulnerability? Europe's Defense Moment Is Now

The transition from a US- to a Europe-led security order is no longer theoretical. It is underway. The Trump administration's announced reduction in American military capabilities in Europe and the undertaking of a broader force review marks the first step in a structural burden-shift that no successor is likely to reverse. Whether that shift opens a window of opportunity or of vulnerability depends on the speed and sustainability of Europe’s response, and on Washington’s view of a stronger European industrial base as an asset or a competitive threat. 

European NATO members and Canada raised defense spending by 20% in real terms in 2025, bringing their combined total to $574 billion. For the first time since the benchmark was set in 2014, every NATO ally met the 2%-of-GDP target for such outlays. Yet the central paradox is stark: Europe is beginning to spend for wartime while still procuring and planning for peacetime. Closing that gap is the defining defense policy challenge of this decade, and it requires three urgent measures.

First, align procurement with threat reality and use Ukrainian expertise. Defense budgets are rising, but the institutional machinery governing their expenditure remains fragmented, slow, and risk-averse. The EU's defense industrial base is still structured around national champions, redundant capabilities, and political horse-trading rather than operational requirements. With a 3.5%-of-GDP spending target coming into force by 2035, EU member states that are also in NATO will collectively represent a defense market of roughly $1 trillion annually. Without fundamental reform of procurement rules, joint tendering, and interoperability standards, however, the extraordinary amount of funds risks being squandered on duplication. The ReArm Europe plan is a start, but ambition must be matched by ruthless industrial pragmatism.

Europe faces a real dilemma: rebuilding its defense-industrial base for long-term autonomy while urgently closing immediate capability gaps. These goals are not mutually exclusive, but they require balancing. Strong political will and financial commitment do not automatically produce rapid increases in production. 

Long-range strike is the most pressing gap. Europeans must plan for the possibility that US assets, even those previously committed, will be unavailable, but the European Long-Range Strike Approach (ELSA) may not deliver a new missile generation until 2030. The ability to square that circle lies, in part, in Ukraine. The country is no longer simply a recipient of Western military support; it is becoming a co-architect of European security. New corporate partnerships—MBDA with Ukraine's Flamingo cruise missile, Diehl with the Neptune—illustrate how European defense firms are moving from supplying Kyiv to co-developing combat-proven technology for NATO's arsenal. Ukraine's “drone deal”, joined by 27 countries including 15 NATO members, and the EU-Ukraine Drone Alliance, launched in May, mark a structural shift in Europe’s approach to defense production. The country brings what no procurement process can manufacture: systems tested under live fire, weapons iterated in days, and a defense culture shaped by existential necessity. Europe brings industrial scale, capital, and NATO's supply chains. Together, they are turning strategic complementarity into hardware.

Second, include the private sector. Defense and security policy in Europe has long been the preserve of governments and militaries. That model is obsolete in an era when the most consequential capabilities—autonomous systems, AI-enabled intelligence, cybersecurity, and satellite communications—are being built in commercial labs. Recent moves by European tech company CEOs to shape EU policy signal that industry is ready to step up. Policymakers must meet them halfway and treat technology companies not as contractors but as strategic partners that must be in discussions to set industrial priorities.

Third, reframe the transatlantic bargain as strategic complementarity. Washington must encourage Europe to build its own industrial base, not treat it as a competitive threat. Strategic complementarity—not dependency—is the model that works for both sides. It distributes the burden, deepens interoperability, and ensures the alliance's combined industrial capacity exceeds the sum of its parts. Complementarity is particularly apparent in defense technology. The United States leads in AI-enabled systems, space-based intelligence, and autonomous platforms; Europe's strengths lie in advanced manufacturing, sovereign cyber capabilities, laser technology, and a rapidly maturing dual-use deep tech ecosystem. Joint production arrangements and co-development frameworks structured through NATO can turn these complementary strengths into a genuine force multiplier.

Fourth, Ankara is the moment. The Pentagon's six-month force review could lead to opportunity or vulnerability. If European governments respond with speed, coordination, and real industrial ambition—accelerating joint procurement, closing capability gaps, and building a defense-tech ecosystem that complements US assets—they become strategic enablers for a more balanced, resilient alliance. If the response is mismanaged—undermined by political fragility, industrial inertia, or a Washington posture that treats European industrial efforts a competitive threat—the West will become acutely vulnerable. Adversaries are watching for signs of fracture.

The NATO summit in Ankara should be the moment allies stop relitigating the terms of the alliance and formalize a new framework of strategic complementarity through agreed capability targets, a transatlantic defense innovation compact, and a shared framework for managing the transition without breaking the alliance. 

The convergence of the Ukraine and Iran conflicts has done what years of strategic dialogue could not: It has crystallized transatlantic interdependence in concrete, operational terms. NATO is being renegotiated, and the terms that emerge will shape European security for a generation. The window of opportunity is open but it will not remain so for long. Ankara is where a new bargain should be struck.