US Report of Possible Spain NATO Suspension Draws Alliance Denial

A leaked internal Pentagon email proposing Spain's suspension from NATO over its refusal to support US military operations in Iran has no legal basis under the alliance's founding treaty — but the episode exposes fractures that run far deeper than one country's defense budget.

The Email

On April 24, 2026, Reuters reported the existence of an internal Pentagon email circulating at senior levels of the US Department of Defense [1]. The email outlined a menu of punitive options against NATO allies that had refused to provide access to bases, overflight rights, and other support — collectively known as ABO (access, basing, and overflight) — for US military operations against Iran [2].

Spain was the most prominent target. The email proposed suspending Spain's NATO membership and removing "difficult" countries from prestigious positions within the alliance [3]. It also floated re-evaluating Washington's support for the United Kingdom's sovereignty over the Falkland Islands — a threat directed at another ally that had initially restricted US base access before permitting use for what Prime Minister Keir Starmer termed "defensive purposes" [4].

Pentagon Press Secretary Kingsley Wilson did not deny the email's existence. "The War Department will ensure that the president has credible options to ensure that our allies are no longer a paper tiger and do their part," Wilson said [1]. Defense Secretary Pete Hegseth was more direct: "The time for free-riding is over. America and the free world deserve allies who are capable, loyal" [4]. Hegseth added that Europe needs the Strait of Hormuz "much more than we do" [4].

No Legal Mechanism Exists

NATO's founding document, the North Atlantic Treaty of 1949, contains no provision for suspending or expelling a member state [5]. Article 13, the only clause addressing departure from the alliance, allows a member to voluntarily withdraw after providing one year's notice to the United States, which serves as the treaty's depositary government [6]. The treaty is silent on involuntary removal.

A NATO official confirmed this reading unambiguously: "NATO's Founding Treaty does not foresee any provision for suspension of NATO membership, or expulsion" [5].

Amending the treaty to create such a mechanism would require unanimous consent from all 32 member states — including, by definition, the country targeted for removal [6]. In the United States, domestic law adds a further constraint: legislation signed by President Biden in 2023 prohibits the president from suspending, terminating, or withdrawing from the North Atlantic Treaty without a two-thirds Senate supermajority or an Act of Congress [7].

The email's proposal, then, describes something the US cannot unilaterally do. Dr. Patrick Bury, a defense analyst quoted in Euronews, noted that Spain's suspension would be "legally impossible" without a "material breach of process" — and even then, no such procedure exists [2].

The Timeline: From Base Denial to NATO Threat

The Pentagon email is the latest escalation in a dispute that has been building for nearly two months.

In early March 2026, as US and Israeli military strikes against Iran intensified, Spain's government formally denied the United States permission to use the jointly operated Rota Naval Station and Morón Air Base for offensive operations [8]. Spain's defense minister stated that "neither the bases are authorised, nor, of course, is the use of Spanish airspace authorised for any actions related to the war in Iran" [9].

The decision forced approximately 15 US aircraft — primarily KC-135 tankers — to relocate from Spain to Ramstein Air Base in Germany and other NATO facilities [10]. US bombers subsequently faced longer mission profiles to reach Iranian targets, a logistically significant complication [11].

President Trump responded on March 3 by threatening to "cut off all trade with Spain," calling the country "terrible" [8]. Prime Minister Pedro Sánchez hit back, declaring: "No to war. Spain says no to war" and describing the US-Israeli strikes as a "disaster" [8].

On March 30, Spain escalated further by formally closing its airspace to US military aircraft involved in the Iran campaign [12]. Secretary of State Marco Rubio publicly questioned the value of US bases in Europe: "What's in it for us?" [13].

The April 24 Pentagon email represents the furthest the US has gone in converting these frustrations into a concrete — if legally unenforceable — threat against a NATO ally.

Spain's Defense Spending: From Laggard to Compliant

One strand of Washington's criticism of Spain concerns defense spending. But the data complicates the narrative.

Source: NATO

Data as of Aug 29, 2025CSV

As recently as 2020, Spain spent just 1.02% of GDP on defense — roughly half the NATO target of 2% [14]. The trajectory improved slowly: 1.03% in 2021, 1.05% in 2022, 1.14% in 2023, and 1.28% in 2024 [14]. Then, in a dramatic acceleration, Spain reached an estimated 2.10% of GDP in 2025, fulfilling the alliance's longstanding benchmark four years ahead of its own 2029 deadline [15].

This placed Spain in a large cohort. By 2025, all 32 NATO members met or exceeded the 2% threshold for the first time in the alliance's history — up from just three countries in 2014 and seven in 2022 [16]. Sixteen allies, however, were barely above the line, with spending estimated between 2.0% and 2.1% of GDP [16].

Source: NATO

Data as of Aug 29, 2025CSV

Where Spain stands alone is on the new target. At the June 2025 NATO Summit in The Hague, all 31 other member states committed to reaching 5% of GDP in defense and security spending by 2035, with 3.5% allocated to core military needs and 1.5% to areas like cyber and infrastructure [17]. Spain secured a formal exemption — the only ally to do so — with Sánchez insisting that 2.1% was "sufficient and realistic" and that a 5% target was "disproportionate and unnecessary" [17]. Trump labeled this "very terrible" and threatened that "Spain will pay double" in future trade talks [17].

What Spain Actually Contributes

The spending figures, however, do not capture Spain's operational footprint. Spain maintains approximately 3,000 military personnel deployed across 17 overseas missions on four continents [18]. Key deployments include:

• Latvia: Roughly 310 troops in NATO's Enhanced Forward Presence mission deterring Russian aggression, plus 128 personnel in Baltic Air Policing [18]
• Iraq: 463 soldiers and civil guards in Operation Inherent Resolve, including a Special Operations Task Group [19]
• Slovakia and Romania: Additional deployments on NATO's eastern flank [10]
• Maritime: Command of EUNAVFOR Atalanta, the EU's counter-piracy mission in the Indian Ocean [18]

Spanish Leopard tanks are stationed at the Adazi base in Latvia, and Spanish fighter jets conduct routine air policing over the Baltic states [10].

Meanwhile, the US bases in Spain that are now at the center of the dispute host approximately 4,000 American military personnel [10]. Naval Station Rota is home to five Navy destroyers — with a sixth expected in fall 2026 — and forms a central component of European ballistic missile defense [10]. The base provides rapid-response capability to the eastern Mediterranean, Red Sea, and Persian Gulf [10]. Morón Air Base houses US Africa Command's Special Purpose Marine Air-Ground Task Force [10].

Analyst Yago Rodriguez has noted that Spain's bases offer "proximity to the Strait of Gibraltar, a strategic chokepoint and gateway to the Mediterranean Sea," enabling submarine and electromagnetic surveillance operations [10]. Retired Navy Captain Jan van Tol warned that these facilities are "hard, expensive and slow to replace" [10].

In other words, suspending Spain would not just punish Madrid. It would create a significant gap in US force projection toward the Middle East and Africa.

The Burden-Sharing Argument

There is a case to be made — and some in Washington are making it — that allowing allies to benefit from collective defense while publicly opposing alliance operations creates a structural problem.

The logic runs as follows: NATO's credibility depends on the perception that its members act in concert. When a member state not only refuses to contribute to a major US military campaign but actively denies base access and airspace, it signals to adversaries that the alliance can be fractured. If this behavior carries no consequences, other allies may calculate that they too can opt out of costly commitments while retaining the Article 5 security guarantee.

Hegseth's argument about the Strait of Hormuz — that European economies depend on it more than America's — carries a factual kernel. Europe imports a larger share of its oil through the strait than the US does [4]. Spain's position that Iran operations violate international law, while consistent with its domestic politics, does strain the alliance norm of mutual support.

But the counterarguments are substantial. France and Spain both denied the US use of their airspace and bases during the 1986 bombing of Libya — a precedent that did not lead to suspension threats [2]. NATO has historically tolerated significant disagreement among members, including France's 43-year withdrawal from NATO's integrated military command structure (1966–2009) and Turkey's repeated vetoes of NATO defense plans for other members.

The 2% spending issue also undermines the consistency of the burden-sharing argument. If spending compliance were the standard, the US would have had grounds to target the majority of NATO members for most of the alliance's existence. The fact that Spain is singled out while equally or recently non-compliant allies are not suggests the real trigger is the Iran war dispute, not defense budgets.

How Allies Responded

Spain's Sánchez, arriving in Cyprus on April 24, refused to engage directly with the email's contents. "We do not work with emails. We work with official documents and positions taken, in this case, by the government of the United States," he said, reaffirming "absolute collaboration with the allies, but always within the framework of international legality" [3].

Germany indicated that "Spain is a member of NATO. And I see no reason why that should change" [4]. Italy's Prime Minister Giorgia Meloni stated NATO "must remain united" [4]. A British spokesperson said the UK's position on the Falklands "is unchanged. Sovereignty rests with the UK" [4].

NATO Secretary General Mark Rutte did not directly address the email but has previously warned that "anyone who believes Europe can defend itself without the United States is dreaming" [20].

The Strategic Autonomy Question

The episode lands in the middle of an accelerating European conversation about defense independence. The EU's Defense Readiness Roadmap 2030, agreed by the 27 EU member states, aims to achieve military-security readiness and strategic autonomy by the end of the decade, with major defense investments beginning in 2026 [21].

Spain's position is paradoxical. Sánchez has been one of the loudest advocates for EU defense autonomy, rejecting the 5% NATO target partly on the grounds that it could undermine EU-level defense planning [17]. Yet Spain's own military capacity — at 2.1% of GDP and with roughly 3,000 deployed personnel — is far from sufficient to replace the security umbrella NATO provides.

Rutte's January 2026 warning to the European Parliament — that building a fully separate European defense posture would be "ruinously expensive" — remains the central constraint on the autonomy debate [20]. The Pentagon email, however intentionally or not, strengthens the hand of those in Europe who argue that dependence on the United States has become a strategic liability rather than an asset.

What the Leak Signals

The identity of whoever shared the email with Reuters remains unknown. The source spoke on condition of anonymity and confirmed that the document was "circulating at high levels in the Pentagon" [1].

Two readings of the leak are plausible. The first is that it was authorized or tacitly approved — a deliberate signal to Spain and other reluctant allies that Washington is willing to escalate. The Pentagon spokesperson's non-denial and combative framing ("paper tiger," "credible options") supports this interpretation [1].

The second is that the leak came from within the national security apparatus as a warning — an effort by officials alarmed at the idea of weaponizing alliance membership to expose the proposal to public scrutiny before it could advance further. The fact that the email's options are legally unworkable may itself be the point: someone wanted to demonstrate that the Pentagon was entertaining ideas untethered from what NATO's treaty actually permits.

Either way, the leak reveals a bureaucracy divided over whether alliance membership should function as a bilateral political lever. That internal debate, more than any specific threat to Spain, may be the most consequential element of the story.

A Precedent Without Precedent

No NATO member has ever been suspended or expelled. No NATO member has ever withdrawn. The alliance has absorbed disagreements over Suez, Vietnam, Iraq, Libya, and Turkey's 2019 incursion into Syria without resorting to membership threats.

What makes the current episode distinct is not the scale of the disagreement — Spain's refusal to support Iran operations is well within the range of historical allied dissent — but the willingness of senior US officials to float, in writing, the idea of using membership itself as a weapon. Whether that idea was serious or performative, its existence in a document circulating at high levels of the Pentagon marks a departure from 77 years of alliance practice.

The North Atlantic Treaty was designed to bind democracies together against external threats. It was not designed to compel members into specific military operations. The absence of an expulsion clause is not an oversight — it reflects a foundational judgment that the alliance's value lies in its voluntarism. The Pentagon email tests whether that judgment still holds.