The Transatlantic Shift: Europe Confronts Strategic Autonomy as US Drawdown Accelerates

On 1 May 2026, US Defense Secretary Pete Hegseth signed the order withdrawing 5,000 American troops from bases in Germany, executing a directive President Donald Trump had threatened for weeks amid a deepening feud with German Chancellor Friedrich Merz. Within 48 hours, Trump escalated further, declaring the United States would reduce its presence in Germany "a lot further" and threatening additional drawdowns in Spain and Italy. For European security planners, the message was unmistakable: the era of unquestioned American security guarantees is over.

The withdrawal, though numerically modest against the roughly 35,000 US troops still stationed in Germany as of early 2026, carries profound strategic weight. According to Reuters reporting from December 2025, American officials had already communicated to their European counterparts that they must assume primary responsibility for the continent's defense by 2027. The May order transforms that diplomatic message into operational reality, and it arrives at a moment when Europe faces its most volatile security environment since the Cold War.

NATO Secretary General Mark Rutte warned in June 2025 that "Russia could be ready to use military force against NATO within five years." Since then, the tempo of Russian gray-zone operations has only intensified: Russian warplanes have violated Estonian airspace, Russian military hackers have struck Polish energy infrastructure, and Russian drones have repeatedly penetrated Polish territory. European Commission President Ursula von der Leyen has characterized these actions as "a deliberate and targeted gray-zone campaign against Europe." Poland's Prime Minister Donald Tusk, responding to the US withdrawal announcement on 2 May, went further, openly condemning what he called NATO "disintegration" — a stark rhetorical escalation from one of the alliance's most committed members.

The European response to this dual pressure — Russian aggression from the east and American retrenchment from the west — has crystallized with remarkable speed. On 7 May 2026, the Kiel Institute for the World Economy published a landmark paper authored by five of Germany's most prominent defense thinkers: Thomas Enders, former Airbus CEO and president of the German Council on Foreign Relations; Jeannette zu Fürstenberg, president of General Catalyst; economist Moritz Schularick, president of the Kiel Institute; René Obermann, Airbus chairman; and security analyst Nico Lange. Dubbed "Sparta 2.0," the paper argues that European defense sovereignty is not only necessary but achievable — and at a relatively modest cost of approximately €50 billion (US$59 billion) per year over the next decade.

The Sparta 2.0 analysis is notable for its specificity. It identifies ten critical capability gaps that render Europe dependent on the United States across what the authors call the "entire military-effect chain," from satellite-based reconnaissance to battlefield fire control. The gaps include: command-and-control systems, where Europe lacks any counterpart to American defense-technology platforms like Palantir and would need €10 billion to €20-plus billion over three to four years to build sovereign C2 and battle-management capabilities; autonomous systems, requiring €30 billion or more over three to five years to establish mass-production capacity for several million drones and loitering munitions annually; ground-based deep precision strike, costed at €20 billion to €30 billion over three to five years; and air defense across the full spectrum from counter-drone systems to ballistic missile defense, with a total cost envelope of €50 billion. Sixth-generation air combat systems would take a decade or more and cost at least €200 billion. The paper also prioritizes a European equivalent to SpaceX's Starlink for satellite communications, space launch independence, persistent airborne ISR, military cloud and AI infrastructure, strategic airlift, and electronic warfare capabilities.

Crucially, the authors contend that these capabilities are not aspirational science projects. "A high degree of European independence can be achieved within a few years, at a cost that can be financed through the planned budget increases," Enders stated. "Ukraine shows us that this does not take decades." The paper frames the challenge as Europe's "Manhattan Project" — demanding political prioritization of a kind the continent has rarely mustered. The required expenditure, the authors note, corresponds to roughly 10 percent of total European defense spending, or approximately 0.25 percent of continental GDP.

That spending is already rising fast. According to the International Institute for Strategic Studies' Military Balance 2026, global defense expenditure reached $2.63 trillion in 2025, up from $2.48 trillion in 2024, with Europe and the Middle East driving the real-terms increase of 2.5 percent. The European Defence Agency reports that EU member states spent $180 billion more on defense in 2024 than they did in 2021. Germany alone accounted for 30 percent of that increase by doubling its budget; Poland, by nearly tripling its own, contributed 14 percent. France and Italy increased spending by 41 and 35 percent respectively.

Poland's rearmament merits particular attention. As the frontline state on NATO's eastern flank, Warsaw is acquiring enormous quantities of munitions, artillery, armor, and air defense systems. Its economy, growing faster and carrying lower debt than the European average, has given it fiscal room that larger but more indebted economies like France and Italy lack. Poland's defense budget now exceeds 4 percent of GDP, among the highest ratios in the alliance, and it has emerged as the indispensable conventional covering force for any credible defense of the Baltic states and the Suwałki Gap.

The institutional architecture of European defense is also evolving. On 19 May 2025, the United Kingdom and the European Union concluded a comprehensive Security and Defence Partnership — the most ambitious framework for UK-EU defense coordination since Brexit. The pact establishes regular consultations between UK Foreign and Defence Secretaries and EU counterparts, an annual Security and Defence Dialogue, and structured cooperation on maritime security, cyber threats, counter-disinformation, and crisis management. Both sides have committed to coordinating against Russia's sanctions-evading "shadow fleet" of oil tankers and to the protection of subsea infrastructure. The agreement also opens the door for UK participation in EU defence initiatives including PESCO Military Mobility, and contemplates UK involvement in future EU military and civilian missions on a case-by-case basis.

Prime Minister Sir Keir Starmer described the partnership as "vital" in what he called a "dangerous new era," emphasizing that the deal would open access to the EU defence fund and create opportunities for the British defence industry. For the EU, bringing the UK — still Europe's largest defense spender after Germany and its only nuclear power alongside France — into a structured defense relationship represents a significant strategic insurance policy against American unpredictability.

The EU's own fiscal instruments are expanding, albeit modestly relative to the scale of the challenge. The 2026 EU budget, agreed by negotiators from the European Parliament and member states, allocates approximately €190 billion overall, with planned spending on security and defence rising by nearly €200 million to a total of €2.8 billion. The EU's far more significant Security Action for Europe (SAFE) programme will channel up to €175 billion in Brussels-backed loans toward joint weapons procurement, with the first disbursements expected in early 2026. As a 2026 analysis from the European Parliament's think tank notes, the European Defence Fund now spends approximately $4.6 billion annually on coordinated weapons research and procurement — still only 1 percent of members' combined defense budgets, but a foundation that is growing.

On the operational front, US Army Europe and Africa is leading the Sword 26 exercise series across the High North, Baltic region, and Poland from late April through May 2026. Formerly known as DEFENDER, the renamed exercise validates NATO's Eastern Flank Deterrence Initiative (EFDI) and tests advanced technologies including AI-enabled command and control, multi-domain operations, and counter-drone systems. General Christopher Donahue, commanding general of USAREUR-AF, described Sword 26 as testing "lethality and ability to harness data and AI-enabled warfare at scale." The exercises incorporate three linked components — Saber Strike, Immediate Response, and Swift Response — operating from distributed locations that underscore the alliance's shift toward dispersed, networked operations designed to complicate adversary targeting.

These exercises carry an irony that is unlikely to be lost on European planners: they demonstrate NATO's continued operational integration at precisely the moment when the political foundation of the transatlantic alliance is being questioned more fundamentally than at any point since 1949. The exercises prove that European and American forces can fight together effectively. The political question is whether they will.

The Foreign Affairs analysis published earlier this month, titled "Europe's New Defense Core," argues that European security for the foreseeable future will depend not on Brussels institutions but on the defense decisions of four states: Germany, which must mobilize its industrial and fiscal weight; Poland, which has no choice but to provide the formidable covering force against any initial Russian attack; and France and the United Kingdom, the only European states with nuclear weapons and expeditionary force-projection capabilities. This "division of labor" framework, the authors contend, is unlikely to produce stronger collective EU defense institutions, but can provide sufficient deterrent capability against Russia to fill the gaps the United States appears determined to leave.

The timeline is compressed. NATO's own assessment gives Europe perhaps five years before Russia reconstitutes sufficient combat power to pose a conventional military threat. The Sparta 2.0 authors frame three to five years for substantial progress toward autonomous European capability and five to ten years for "far-reaching autonomy." US officials are privately pointing to 2027. What happens in the next 18 months — in European defense budgets, in industrial mobilization, in political coordination — will likely determine whether the continent achieves strategic adulthood or faces a future of heightened vulnerability in a more dangerous world.