Even as Europe races to rearm and reduce its strategic dependence on the United States, two new studies show just how deeply the continent still relies on American weapons, technology and command structures.
Far from easing, Europe’s dependency is hardening: a historic surge in military spending has produced a buying spree of advanced US equipment that will lock European forces into American systems for decades.
This reliance extends well beyond hardware. The command-and-control architecture underpinning European defence dominated by the US through NATO means that in any major conflict on European soil, it would almost certainly be an American general calling the shots.
Together, these twin dependencies shape a profoundly asymmetric transatlantic relationship, one resulting in Europe getting the short end of the stick in other critical dealings such as trade and industrial policy.
“The strategic importance of this defence dependency is huge,” Juan Mejino-López, a research analyst at Bruegel, told The Parliament. “It means that the US has way more leverage when they are negotiating in other fields. And here of course I'm talking about the recent trade deal,” he added, referencing the lopsided June agreement between US President Donald Trump and EU Commission Chief Ursula von der Leyen that imposed a 15% baseline tariff on most European exports and kept in place a sweeping 50% levy on metals.
America’s grip on European defence
A recent Bruegel study by Mejino-López and senior analyst Guntram B Wolff shows how American military sales to Europe have surged since 2022, deepening a dangerous dependency on critical American technology. Between 2019 and 2021 Europe accounted for 27.83% of American military foreign sales exports; between 2022 and 2024, that number jumped to 50.7% in the wake of Russia’s invasion of Ukraine.
Yet the authors caution that import volumes alone can be misleading. Most European governments, with the notable exception of Poland, still channel the bulk of their military contracts to domestic producers. Research by the same authors last year showed that European countries such as Italy, France, Germany and the United Kingdom all spend less than 10% of their defence equipment budgets on imports, favouring homegrown industry instead.
A focus on domestic arms manufacturers has contributed to Europe’s well-known defence fragmentation. European armies use a whopping 12 different main battle tanks, ammunition is often incompatible across militaries, and any one country lacks the R&D funding needed to deliver high-tech capabilities.
However, domestic production has also yielded some successes. Artillery shell production, for instance, has increased six-fold in just two years, jumping past US output and proving that Europe can effectively scale up more quotidian military hardware when the political will exists.
But low import shares mask a deeper dependence: Europe still lacks the high-end military technologies — software, satellites, mid-air refuelling aircraft and advanced fighter jets like the F-35 — indispensable to modern warfare. Here, Europe turns overwhelmingly to the US.
“You create a lock-in effect, because you depend on the US contractor to provide the technology,” said Mejino-López. “The hands on the software are American.”
That lock-in is particularly clear with the F-35: European operators rely on continuous US updates to the aircraft’s ODIN maintenance software and are locked into decades-long contracts. European navies using the American Aegis Combat System are similarly exposed. If Washington stalled or restricted updates, Europe’s most advanced and costly capabilities would degrade quickly.
The reasons for Europe’s shortfall abound: chronic underinvestment, fragmented markets, low research and development budgets, and political infighting. Those problems converged catastrophically in the Future Combat Air System (FCAS) programme, now on the verge of collapse despite its ambition to challenge US dominance in next-generation airpower.
Shifting US command structure to Europe
Weapons dependency is only half the picture. A recent study by the Center for Strategic and International Studies (CSIS) analysts Max Bergmann and Otto Svendsen argues that focusing on actual European military capabilities — rather than just spending numbers — and asserting more sway over command-and-control structures would strengthen continental defence as the US continues to pull support.
But building a European-led command-and-control structure is fraught. Svendsen noted the option to grow the EU’s embryonic military staff, or rely on the “coalitions of the willing” organised in the wake of Russia’s invasion of Ukraine. But both options face a slew of legal and practical hurdles.
An ad-hoc coalition would risk a patchwork of regional defence clusters as major partners such as the UK Germany, and Italy consolidated smaller allies around them to defend different parts of Europe without unified command. Expanding the EU military staff would require a hundredfold increase in personnel and, as Svendsen said, likely violate EU treaty constraints on who can command troops during a crisis.
That leaves a third option: “Europeanising NATO” by placing European generals, rather than Americans, in key leadership roles.
The idea is hardly new, harking back to proposals by Henry Kissinger in the 1980s. But it has regained traction amid concerns about the second Trump administration’s stance towards the alliance.
Since NATO’s founding, Americans have held nearly all leading military positions, while Europeans typically take the political-facing secretary-general role. That’s still the case today. Trump’s July appointment of General Alexus G Grynkewich as Supreme Allied Commander Europe (SACEUR) means that if war were to break out in Europe, an American general reporting ultimately to the White House would be running a war with largely European troops.
While Svendsen called continued US engagement the ideal outcome, Europeans should “be looking to accelerate that conversation to take that [SACEUR] leadership role out of American hands.”
Ironically, the Trump administration supports this shift more than many Europeans do. Last month, the US ambassador to NATO, Matthew Whitaker, said at the Berlin Security Conference: “I look forward to the day when Germany comes to the United States and says that we’re ready to take over the supreme allied commander position. I think we’re a long way away from that, but I look forward to those discussions.” His statement stunned German generals, who insisted the role remains US territory.
Part of the hesitation stems from predictable inter-European squabbling. “It’s always an American, and for good reasons,” said Svendsen. “I mean, this is sort of a question that is endemic to European defence. Are the British going to accept having a French general command British troops if the Russians invade Estonia?”
Arms progress, but command stasis
Europe is making real progress in strengthening its industrial base, according to Mejino-López. The Defence Readiness Roadmap 2030, SAFE funding, ASAP programme, and the European Defence Fund, compounded by huge boosts in national military spending, show that Europe is taking the arms challenge seriously.
Still, he said fragmentation and low R&D spending mean that high-tech dependence on the US will persist in the short to medium term. As Mejino-López notes, America spends 10 times more on defence R&D than Europe – ensuring the transatlantic gap will widen.
On command-and-control, however, momentum is far weaker. Svendsen argued that European reluctance to broach leadership change within NATO possibly stems from a fear of triggering the very US disengagement they wish to avoid. “I don’t think Europe is quite ready to take over full responsibility in a command-and-control sense,” he said.
That’s why Svendsen and Bergmann’s most provocative proposal — a 100,000-strong pan-European army to replace the 80,000 American troops currently stationed in Europe — would be organised under current NATO structures, rather than through a legally dubious EU route. NATO already has the legal authority and capacity to command those troops and, in time, a more assertive European role could emerge within the alliance.
Some momentum exists within the European Parliament for what MEPs call a “European Defence Union.” In October, lawmakers passed a resolution that called for “advances towards a European command-and-control structure that not only manages crises in line with the Common Security and Defence Policy (CSDP), but also serves as the equivalent of NATO’s Supreme Headquarters Allied Powers Europe (SHAPE).”
Still, the resolution stressed that any EU command-and-control infrastructure would be designed to complement, rather than replace, NATO.
Even as pressures mount on both the East and West, the sluggish pace of integration and reorganisation leaves Europe vulnerable if Russia were to launch a sudden attack — especially if the US continues to pull back from the continent. The subtext? America isn’t the same ally it once was, and Europe cannot afford to bet on future US presidents reversing course.
“It's quite clear the direction of travel that the US is in,” said Svendsen. “I don't think we're quite operating with the sense of urgency that we need to be.”
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