One of our editors wanted to know what Swiss neutrality actually requires when Switzerland declares a conflict a war. The answer turns out to be unusually specific.
The Swiss Federal Council officially classified the conflict between the United States, Israel, and Iran as a war on March 13, 2026. Federal Council spokesperson Nicole Lamon confirmed the determination: “There is a war between the USA/Israel and Iran.” The classification was based on the intensity and duration of hostilities meeting the legal threshold under Swiss neutrality law.
Two consequences followed immediately. The United States can no longer fly military aircraft through Swiss airspace. And Switzerland can no longer authorize arms exports to any of the belligerent parties.
What Triggered the Swiss Neutrality Classification
Switzerland distinguishes between neutrality law and neutrality policy, a separation that creates confusion but serves a legal purpose. Neutrality policy is discretionary: it covers Switzerland’s broader diplomatic posture and can be adapted to circumstances. Neutrality law is binding. It derives from the Hague Conventions of 1907, ratified by Switzerland in 1910, and it activates automatically when the Federal Council determines that a conflict qualifies as a war.
The threshold is not a single trigger. Foreign Minister Ignazio Cassis had initially described the situation as a “conflict” and stated that “the threshold for applying Switzerland’s neutrality law had not yet been reached.” By March 13, the Federal Council concluded that the duration and intensity of hostilities met the requirements for reclassification. The shift from “conflict” to “war” was not symbolic. It carried legal force.
Two Overflight Requests, Two Rejections
Two US military overflight requests were rejected before the formal war classification. The Federal Office of Civil Aviation (FOCA) initially attributed the rejections to “procedural reasons,” stating that the applications “required extensive clarification and could not be approved within the specified deadlines.”
That framing was diplomatic. The Federal Council was simultaneously examining whether Swiss neutrality law applied to the conflict. Once the war classification was made on March 13, the procedural ambiguity dissolved. Under the law of neutrality, a neutral state may not permit belligerent military forces to use its territory, including its airspace.
What the Hague Conventions Require of Swiss Neutrality
The obligations come from two instruments: the Fifth Hague Convention (rights and duties of neutral powers in land warfare) and the Thirteenth (naval warfare). The conventions codified rules that had existed in customary international law for centuries, but 1907 gave them treaty force.
The relevant provisions for this situation are straightforward. A neutral state must not allow belligerent forces to move troops or supplies across its territory. It must not provide war material to belligerent states. And it must treat all belligerents equally: whatever is denied to one must be denied to all.
That equal treatment obligation is why Switzerland’s classification names the United States and Israel alongside Iran as belligerent parties. Swiss neutrality requires the restrictions to apply to all three. Switzerland cannot selectively ban Iranian overflights while permitting American ones, or vice versa.
Defense Minister Pfister on International Law
Days before the formal classification, Defense Minister Martin Pfister had already taken a strong position. On March 8, he publicly stated that the United States and Israel had violated international law by attacking Iran. “The Americans and Israel have attacked Iran from the air,” Pfister said. “In doing so, they, like Iran, have violated international law.” The Federal Council’s official position was that “the attack on Iran constitutes a violation of the prohibition on the use of force.”
Pfister also warned that Europe could be drawn into the conflict through asymmetric warfare, including the risk of terrorist attacks on Swiss soil. The statement placed Switzerland among a small number of Western countries to explicitly characterize the US-Israeli campaign as a breach of international law. German Vice Chancellor Lars Klingbeil expressed “serious doubts that this war is legitimate under international law.” Spain similarly denounced the bombings as unlawful.
The Precedents: Kosovo and Iraq
Swiss neutrality has produced this outcome before. During the NATO intervention in Kosovo in 1999, the Federal Council banned US military overflights of Swiss airspace. The reasoning was identical to today’s: no UN Security Council resolution authorized the campaign, so neutrality law applied. Switzerland later permitted overflights for KFOR peacekeeping missions in Kosovo, because those operated under a UN mandate, and UN-mandated operations fall outside the scope of neutrality law.
The same logic applied during the 2003 invasion of Iraq. Switzerland banned combat overflights but allowed humanitarian flights. The distinction was not generosity; it was legal obligation. The Hague Conventions do not prohibit humanitarian passage, only the movement of belligerent military forces and materiel.
The current situation differs from both precedents in one respect: the economic stakes are higher. The United States is Switzerland’s second-largest export market. Switzerland maintains substantial arms and dual-use goods exports to the US. Switzerland recently purchased F-35 fighter jets from Lockheed Martin. Applying neutrality law to the US is not cost-free.
The Neutrality Initiative and Constitutional Reform
These decisions are playing out against a domestic political fight over the future of Swiss neutrality itself. A popular initiative backed by Pro Switzerland and the Swiss People’s Party seeks to enshrine “perpetual and armed” neutrality in the federal constitution, along with a broad ban on sanctions.
If adopted, the initiative would prohibit Switzerland from cooperating with military or defense alliances except in the event of a direct attack on Swiss territory. Only sanctions approved by the UN Security Council could be supported. The current flexibility that allows Switzerland to adapt its neutrality posture to changing circumstances would end.
The Swiss parliament has rejected the initiative. The House of Representatives voted overwhelmingly against it, with only the Swiss People’s Party supporting it. But the Council of States (the upper chamber) approved a counter-proposal on March 12, 2026, by the narrowest possible margin: 21 to 21, with the tie broken by Senate President Stefan Engler. The counter-proposal would constitutionalize “permanent and armed” neutrality without restricting Switzerland’s ability to impose sanctions.
Swiss citizens are expected to vote on the initiative later in 2026. The Iran war has given its proponents their strongest argument in years: that Swiss neutrality needs constitutional protection precisely because geopolitical pressure will always push toward compromise.
The Protecting Power Paradox
Switzerland’s position contains a structural tension that the Hague Conventions did not anticipate. Since 1980, Switzerland has represented US interests in Iran as a protecting power, serving as the primary diplomatic channel between Washington and Tehran. That role has continued through the current war. When European alliances were tested by the conflict’s escalation, Switzerland’s channel remained open.
On March 12, Switzerland closed its own embassy in Tehran due to security concerns but confirmed that the protecting-power mandate for the United States would continue and that the diplomatic line between Washington and Tehran remains active.
This means Switzerland is simultaneously declaring the United States a belligerent party under neutrality law, banning its military overflights, classifying its attack on Iran as a violation of international law, and maintaining the primary diplomatic back channel between Washington and its adversary. The roles are not contradictory under international law. A protecting power is explicitly a neutral intermediary. But the optics require a government confident enough in its legal framework to hold all four positions at once.
What Comes Next
The practical impact of the overflight ban on US military operations is limited. Switzerland’s airspace is small, and US military logistics in the Middle East do not depend on Swiss routing. The significance is legal and political. Each time Swiss neutrality is applied to the United States, it reinforces the framework’s credibility and establishes precedent for future conflicts.
The arms export ban may matter more. Switzerland’s defense industry produces components and dual-use technology that enters US supply chains. How strictly the ban is enforced, and whether existing contracts are grandfathered or suspended, will be the next point of friction.
The constitutional referendum, whenever it reaches a public vote, will determine whether Swiss neutrality remains a policy choice or becomes a constitutional constraint. The difference is significant: a policy can be adjusted by a Federal Council vote. A constitutional provision requires another referendum to change.
For now, the Hague Conventions of 1907 are doing exactly what they were written to do. A neutral state has classified a conflict as a war, applied its legal obligations equally to all belligerents, and accepted the diplomatic and economic costs of doing so. The framework is 119 years old. It still works.
