Overview
In late 2025, the United States quietly told European allies it wants them to assume the majority of NATO’s conventional defense by 2027, including ground forces, air power, and much of the alliance’s intelligence and missile capabilities. The message, conveyed in meetings with diplomats and defense planners, builds on President Donald Trump’s second-term push for allies to spend 5% of GDP on defense and security by 2035, a target formally adopted at the June 2025 NATO summit in The Hague.
Under Defense Secretary Pete Hegseth and a new National Security Strategy that elevates the Western Hemisphere and border security over Europe, the U.S. envisions itself increasingly as NATO’s nuclear backstop and high‑end enabler rather than the primary provider of conventional forces on the continent. The 2027 benchmark raises urgent questions about whether European states can rapidly expand and integrate their militaries, how much the U.S. will actually draw down in Europe, and whether NATO can maintain cohesion while its central pillar deliberately steps back from day‑to‑day defense of the continent.
Key Indicators
People Involved
Organizations Involved
NATO is a 32‑member transatlantic defense alliance whose core mission is collective defense under Article 5 of the Washington Treaty.
The U.S. Department of Defense (DoD) oversees the American armed forces and global military posture.
Timeline
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New U.S. National Security Strategy criticizes Europe and prioritizes Western Hemisphere dominance
Policy DocumentThe Trump administration’s 2025 National Security Strategy warns of European ‘civilizational erasure,’ calls for ‘cultivating resistance’ within Europe, downplays Russia as a primary threat, and prioritizes U.S. dominance in the Western Hemisphere over traditional commitments in Europe.
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Greece approves major Israeli rocket artillery purchase amid regional and alliance pressures
Capability AcquisitionThe Greek parliament’s defense committee approves the purchase of PULS rocket artillery systems from Israel for around €650–700 million, part of a plan to spend €28 billion on defense modernization by 2036, illustrating broader European rearmament dynamics under NATO pressure.
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Hegseth outlines hemispheric-first strategy at Reagan Defense Forum
Policy SpeechDefense Secretary Hegseth declares the end of U.S. ‘utopian idealism’ in foreign policy, emphasizes securing the Western Hemisphere and border as top priorities, and reiterates that allies must take on more defense burdens, aligning with the 2027 NATO benchmark.
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U.S. quietly sets 2027 benchmark for Europe-led NATO conventional defense
Policy LeakReuters reports that Pentagon officials have told European diplomats the U.S. wants allies to assume the majority of NATO’s conventional defense responsibilities, including intelligence and missile capabilities, by 2027, though metrics and enforcement remain unclear.
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Analysts note NATO spending deal likely precedes U.S. force reductions in Europe
Expert AnalysisCommentary from think tanks such as the Centre for Eastern Studies suggests that the 5% agreement will be paired with a review expected to reduce U.S. military presence in Europe over time.
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NATO Hague summit adopts 5% GDP defense target for 2035
Alliance DecisionAt a summit in The Hague, NATO leaders agree to raise total defense and security-related spending to 5% of GDP by 2035, with 3.5% for core military needs and 1.5% for infrastructure, resilience, and related investments. Spain receives an exemption after objecting.
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Trump warns U.S. may not defend under‑spending NATO allies
Public StatementAt the White House, Trump states that he will not defend NATO members that fail to meet spending obligations, reviving fears about the reliability of Article 5 commitments.
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Hegseth: U.S. no longer ‘primarily focused’ on European security
Policy SpeechOn his first major trip to Brussels, Defense Secretary Hegseth says Europe must lead in supporting Ukraine and that restoring its pre‑2014 borders is unrealistic, while calling for much higher European defense budgets.
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Trump publicly calls for 5% of GDP defense spending by allies
Public StatementBefore and shortly after his second inauguration, Trump says NATO members should spend 5% of GDP on defense so the U.S. can focus on its own borders and the Indo‑Pacific, signaling a major escalation in burden‑sharing demands.
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Mark Rutte becomes NATO Secretary General
Leadership ChangeFormer Dutch prime minister Mark Rutte succeeds Jens Stoltenberg as NATO chief, emphasizing the need for a wartime mentality, higher defense spending, and sustained support for Ukraine.
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Russia’s full‑scale invasion of Ukraine accelerates European rearmament
ConflictMoscow’s invasion sparks a major shift in European defense policy, with governments pledging large spending hikes and new capabilities, including Germany’s landmark defense fund and rapid moves by states like Denmark and Belgium to boost budgets.
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NATO sets 2% of GDP defense-spending guideline at Wales summit
Policy CommitmentIn response to Russia’s annexation of Crimea, NATO leaders pledge to move toward spending at least 2% of GDP on defense by 2024, laying the foundation for later, more ambitious targets.
Scenarios
Soft Landing: Europe Nearly Meets 2027 Benchmark, U.S. Scales Back Without Breaking NATO
Discussed by: NATO officials, OSW analysts, major European outlets such as DW and the Financial Times
In this scenario, accelerated European rearmament, higher defense budgets, and industrial ramp‑up allow European allies to credibly field most of NATO’s conventional forces by around 2027–2029, even if some niche capabilities still rely on the U.S. Washington proceeds with a gradual reduction of permanent ground forces in Europe, offset by rotational deployments, pre‑positioned equipment, and continued nuclear and high‑end enabler roles. The 5% target is not fully met by 2035 everywhere, but enough progress satisfies political expectations in Washington. NATO cohesion holds, Europe gains more say in strategy, and the alliance evolves into a more balanced—though increasingly Europe‑led—conventional force structure.
Hard Break: Europe Falls Short, U.S. Rapidly Draws Down and Undermines Article 5 Confidence
Discussed by: Skeptical European parliamentarians, some U.S. restraint advocates, critical commentary in outlets like The Guardian and Washington Post
If European political and fiscal constraints prevent serious movement toward the 2027 goal, Trump and Hegseth could use the shortfall to justify sharp cuts in U.S. conventional forces in Europe and more explicit conditionality on U.S. defense guarantees. This might include relocating brigades to the U.S. or Indo‑Pacific and openly signaling that the U.S. will not fight large conventional wars in Europe. Allies close to Russia, like Poland and the Baltics, react by massively expanding their own militaries and seeking bilateral security deals with the U.S. or UK. Perceptions that Article 5 is politically, if not legally, weakened encourage Russian probing and information operations, and could accelerate European exploration of independent nuclear or strategic options.
Managed Delay: Deadlines Slip, Metrics Soften, and NATO Adopts a ‘Good Enough’ Standard
Discussed by: Many European defense planners, think tanks such as the Centre for Eastern Studies, pragmatic voices in Washington
Recognizing the difficulty of rapidly building complex capabilities and industrial output, NATO quietly treats 2027 as a political signal rather than a hard deadline. The 2029 review built into the 5% framework becomes an opportunity to stretch timelines, redefine what counts as ‘defense‑related’ spending, and focus on qualitative capability benchmarks instead of purely numerical spending metrics. The U.S. still reduces some forces in Europe but maintains enough presence to reassure front‑line allies, while Europe continues incremental rearmament. Tensions over rhetoric and domestic politics persist, yet the alliance muddles through without a clear rupture.
European Strategic Autonomy Breakout: EU-Led Defense Structures Partially Decouple from NATO
Discussed by: Advocates of European ‘strategic autonomy’, some French and EU policy circles, long‑term scenario work in European think tanks
In a more radical trajectory, sustained U.S. pressure, ideological clashes (e.g., over the NSS language about Europe), and perceived unreliability of U.S. commitments drive EU states—especially France and potentially Germany—to deepen EU‑centric defense frameworks (PESCO, joint command structures, and industrial initiatives). NATO remains formally intact, with the U.S. still providing nuclear deterrence, but key parts of planning, procurement, and rapid‑reaction forces are organized under EU or ad‑hoc European umbrellas. Over time, Washington may welcome this as burden offloading, but overlapping structures risk duplication, coordination challenges, and political divergence, especially if EU forces are used in ways Washington opposes.
Crisis Trigger: A Shock in Ukraine or the Baltics Tests the New Division of Labor Prematurely
Discussed by: Security hawks, Baltic and Polish officials, some U.S. and UK defense commentators
A sudden escalation—such as a major Russian offensive in Ukraine or a destabilizing incident in the Baltic region—could test the emerging burden‑sharing model before European capabilities are ready. European allies might be forced to improvise large‑scale deployments and sustainment with limited U.S. ground participation, while Washington focuses on intelligence, logistics, and nuclear deterrence signaling. If Europe performs well, it could validate the push for self‑reliance. If it struggles, pressure would mount either for a return of U.S. forces or for more radical European defense integration, with high stakes for alliance credibility.
Historical Context
The Nixon Doctrine and Asian Burden-Sharing (1969)
1969–1975What Happened
In 1969, President Richard Nixon announced the so‑called Nixon (or Guam) Doctrine, stating that the U.S. would assist allies with economic and military aid but would no longer send large ground forces to defend them except against major nuclear powers. This underpinned Vietnamization—shifting the combat role in Vietnam to local forces—and similar expectations placed on allies like Iran and South Korea.
Outcome
Short term: The U.S. reduced troop deployments in Asia and transferred more responsibility and equipment to regional partners while maintaining nuclear guarantees.
Long term: Vietnam ultimately fell to North Vietnamese forces in 1975, highlighting limits of rapid localization of security responsibilities even as the broader doctrine influenced later burden‑sharing debates.
Why It's Relevant
The current U.S. push for Europe to assume NATO’s conventional defense while Washington retains a nuclear and high‑end role closely mirrors the Nixon Doctrine formula—support and nuclear umbrella, but far fewer U.S. troops. It highlights both the appeal and risks of shifting burdens too quickly to allies whose forces and politics may not yet be ready.
Mansfield Amendments and Debates on U.S. Troops in Europe (Late 1960s–1970s)
1966–1974What Happened
During the late 1960s and early 1970s, Senator Mike Mansfield repeatedly proposed amendments to sharply cut U.S. troop levels in Europe, arguing that European allies should pay more and that American deployments strained U.S. finances. Although his amendments failed, the debates forced consideration of burden-sharing and the economic costs of stationing troops abroad.
Outcome
Short term: The U.S. ultimately kept large forces in Europe, but NATO allies increased some contributions and costs became a persistent theme in alliance politics.
Long term: Mansfield’s efforts prefigured later waves of burden‑sharing pressure—including Trump’s—demonstrating that questions about U.S. troop levels in Europe recur whenever domestic fiscal or strategic priorities shift.
Why It's Relevant
Today’s 2027 benchmark and potential U.S. drawdown echo the Mansfield era’s arguments about the cost of troops in Europe and whether allies are paying enough. The difference is that now Russia is more openly revisionist and European societies are more accustomed to low defense spending, raising the stakes of any reduction.
Trump’s First-Term Clash with NATO Over Spending (2017–2020)
2017–2020What Happened
In his first term, Donald Trump publicly berated NATO allies for under‑spending on defense, demanded they pay ‘their fair share,’ and even suggested raising the target to 4% of GDP at the 2018 Brussels summit. He hinted that the U.S. might not automatically defend allies that failed to meet obligations, alarming European governments.
Outcome
Short term: More allies moved toward or above the 2% spending guideline by 2024, in part to reduce political friction with Washington and respond to Russia’s aggressiveness.
Long term: The experience conditioned European leaders to see Trump’s second‑term demands as both a serious risk and a bargaining environment, paving the way for the 5% compromise at The Hague and the current debate over how far the U.S. will actually pull back.
Why It's Relevant
Trump’s earlier confrontations set the psychological and political stage for the current 5% target and 2027 benchmark. They demonstrate that while shock tactics can move allies on spending, they also create enduring doubts about U.S. reliability that now shape European thinking on strategic autonomy and contingency planning.