Legal assessments of the ongoing Israel-US hostilities with Iran have thus far been largely characterized by a binary framework. Criticisms have focused on the manifest disregard for the UN Charter and the law governing self-defence. Supportive assessments have either contorted the Charter requirement of imminence beyond recognition—or simply looked past it to frameworks that espouse the “illegal but legitimate” language or focus on “self-preservation”.

Notwithstanding continued academic sparring over the legality of the initial resort to force itself, this post draws attention to two recent examples of state practice in response to the ongoing hostilities. First, Switzerland and Sri Lanka have determined that the ongoing conflict constitutes a war—thus triggering the application of the law of neutrality. Second, the passage of resolution 2817 by the UNSC, wherein it upheld the navigational rights of all states not party to the ongoing hostilities.

This state practice is important. The first development confirms that in any assessment of belligerent-third state relations, the UN Charter is not the sole frame of reference: equally important is the Hague law governing neutrality, specifically Hague Conventions V and XIII. Hague Convention V governs the rights and duties of neutral powers and persons in case of war on land, whereas Hague Convention XIII governs the rights and duties of neutral powers in naval war. Although the Hague conventions have a limited number of state parties, much of their content is widely regarded as declaratory (p.215) of customary international law.

The second development confirms that the existence of a state of war is not, ipso facto, incompatible with the existence of a charter-governed international order. Ever since the entry into force of the UN Charter, there has been a recurring debate about the relevance of the law of neutrality (for a recent negative view, see here). This debate has centered on whether it is still possible to remain neutral, given a state’s collective security obligations and the prohibition on the illegal use of force. UNSC resolution 2817 demonstrates the continued co-existence of these two bodies of law.

Switzerland and Sri Lanka’s determination of “war” and the application of neutrality

Almost all international armed conflicts since 1945 have been fought without a recognition of the state of war. However, nothing in international law precludes a state of war from arising, simply because hostilities commence absent a declaration of war. Third states can and do probe independently into the nature of the hostilities for purposes of determining the application of the law of neutrality. This remains possible because of the distinction between war in a technical sense (which requires a declaration of war) and war in the material sense—the latter depending solely on the actual use of armed force, that is comprehensive on the part of at least one of the parties.

This distinction is crucial, because while the concept of a state of “war” has been in a progressive decline (para 277), it does continue to remain critical for purposes of the application of the full range of the rights and obligations inherent in the law of neutrality. IHL may apply the moment an armed conflict breaks out, but the law of neutrality does not. There is no automaticity (Seger, p.253) between the application of these two bodies of law. This is because while IHL is triggered by a very low threshold, the law of neutrality is not automatically applicable (para 1.3, p.74) without a consideration of the scale and duration of the hostilities.

This understanding, which is reflected across state manuals (e.g., para 3.2.3, p.29), in the ICRC’s commentaries (para, 275) and leading academics (e.g., pp. 31-32) is a recognition of the point that the application of neutrality depends upon the existence of a “generalized state of hostilities”—a notion which corresponds (pp.605-608) to war “in the material sense”. This is the reason why the domestic imbroglio in the USA regarding the War Powers Resolution has no bearing on the determination of the existence of a state of war for the purpose of concluding whether or not the law of neutrality has become applicable.

Switzerland has famously served as a bellwether for ascertaining the existence of a state of war, given its meticulous and sustained engagement with the law governing neutrality. Most recently, it invoked its neutrality during the Kosovo conflict in 1998-1999, the 2003 Iraq War and in response to the conflict in Ukraine. Crucially, when invoking neutrality concerning Ukraine, Switzerland adopted a much stronger stance in response to the 2022 armed conflict than to the 2014 annexation of Crimea. In 2014, it applied sanctions in a measured fashion, choosing to apply only those EU sanctions which related directly to the annexation. However, in 2022, it adopted the first EU sanctions packages against Russia in their entirety (see pp.17-18 and 19-20 here; the English version is available here). Switzerland justified this stance by noting that the scale and magnitude of the 2022 conflict distinguished (p.20, p.19 in the English version here) it from the 2014 conflict.

Following the outbreak of the current hostilities, while Switzerland did denounce the attacks on Iran as a breach of international law, it did not automatically apply the law of neutrality. Even with the conflict entering its second week, Switzerland had not determined that the threshold for applying its neutrality law had been reached. However, on 13 March 2026, it was reported that Switzerland had concluded that the hostilities between USA/Israel and Iran qualify as a war and hence the law of neutrality applies. Pursuant to this, it has already rejected US flyover requests which related to the Iran war, while permitting humanitarian and medical transits. It has also made the decision to halt weapons exports, stating that it will no longer issue licenses for companies to export war materials to the USA.

Switzerland has been one of the few states which still actively invokes the Hague Conventions in support of its stance on neutrality. Notably, its determination is in addition to an independent determination made by Sri Lanka. On 4 March 2026, the USS Charlotte (SSN-766) torpedoed the IRIS Dena in Sri Lanka’s Exclusive Economic Zone (EEZ), many of whose sailors were subsequently rescued by Sri Lanka. As the first time a US submarine has sunk an enemy warship by torpedo since World War II and only the fourth time that any submarine has sunk a warship since World War II, this incident attracted considerable attention.

However, following the sinking of the IRIS Dena, the IRIS Bushehr requested entry into Sri Lankan ports on the very same day (4 March). Explicitly affirming its own neutral status, Sri Lanka recognized that the Iranian naval vessels belonged to a “party in a war” and interned the IRIS Bushehr at Trincomalee and its crew at Colombo. Additionally, it refused permission for two armed US combat aircraft to land at a civilian airport from March 4—8, since accommodating such a request would have been inconsistent with its neutrality.

With respect to the naval crew, Sri Lanka expressly distinguished between the personnel of the IRIS Dena (rescued following its sinking) and the personnel of the IRIS Bushehr—who have been interned. It has pointed out that the former are governed by IHL and its provisions on repatriation. However, the status of the personnel of the IRIS Bushehr is governed by the Hague law of neutrality, thus mandating that Sri Lanka detain them until the end of the hostilities. Amongst the many fascinating issues that arise from this episode is the question of the interaction between the Geneva Conventions and the Hague law of neutrality, which is addressed in greater detail in a separate post by Pornomo Yoga.

UNSC Resolution 2817

Purporting to act in self-defence in response to the Israeli/USA attacks, two courses of Iranian action are of interest to us here. First, Iran declared that “all bases, facilities, and assets of the hostile forces in the region shall be regarded as legitimate military objectives.” It then struck these bases, facilities and assets in Bahrain, Kuwait, Qatar, the United Arab Emirates, and Saudi Arabia—even those from where no attacks have originated. Second, Iran announced that the Strait of Hormuz is closed and that it would fire on any ships undertaking the passage. It commenced mine-laying operations and attacked numerous merchant vessels (for a list of the vessels struck thus far, see here).

In the early days of the conflict, Adil Haque had noted that whatever the merits of Iran’s claimed right of “self-defence” in targeting American bases, facilities and assets, there is no legal basis for its actions overriding “the legal rights of uninvolved third states.” It is in this context that UNSC Resolution 2817—co-sponsored by 135 member states—assumes salience. The resolution itself is curiously silent about the roles of the USA and Israel in the current conflict. Of importance for the current post though, is its reaffirmation of the “right of navigation for shipping en route to and from all ports and installations of the littoral States that are not parties to the hostilities.” Reaffirming the need to respect the navigational rights and freedoms of merchant and commercial vessels, it noted that, “any attempt to impede lawful transit passage or freedom of navigation in…international waterways constitutes a serious threat to international peace and security.”

The use of the phrase, “States that are not parties to the hostilities” is legally significant, as it confirms that irrespective of the basis on which inter-belligerent relations are conducted, belligerent third state relations do continue to operate under the Charter framework. This is because the relationship between a neutral and a belligerent remains one of a state of peace. Having said this, it must be acknowledged that there currently exists a fierce debate in international law about the status of neutrality. The debate particularly centres on the questions of whether the status of neutrality is automatic or optional and whether or not international law recognises only a binary distinction between neutral and belligerent status. This latter point is connected to the debate about the status of qualified neutrality and non-belligerence (for a summary of the wide range of views expressed in this debate, see Ronzitti at pp.65-66 Wentker at pp.66-69 and Schmid).

As explained by Kolb and Meret, the principal difference between qualified neutrality and non-belligerency is that qualified neutrality maintains the premise that a state may only be a neutral or a belligerent. Additionally, qualified neutrality insists that the state which supports the victim state against the aggressor can retain its neutral status even as it derogates from the duties of abstention and impartiality. The problem with “qualifying” neutrality, though, is that this would empty neutrality of its substance. To furnish military assistance to one belligerent but still claim to be neutral is a contradiction in terms. In sharp contrast, non-belligerency accepts a third, intermediate status between neutrality and belligerency. Such a status allows a state to not directly participate in a conflict whilst militarily sustaining one party.  

Currently then, certain authors deny that a half-way intermediate status has crystallised in international law (Wentker at p.68), whereas others find such a status to be hardening into a customary rule of general international law (Kolb, at pp. 215-219). Unpacking these debates is a task beyond the remit of this post. However, it can be safely noted that interference with vessels or aircraft belonging to States claiming the status of non-belligerency or qualified neutrality raises more complex legal questions than interference with those adhering to ordinary/strict neutrality. It suffices, then, to note that regardless of one’s position on non-belligerency or qualified neutrality, a core category of States remains that observe ordinary/strict neutrality, and interference with their vessels or aircraft will certainly violate the UN Charter’s prohibition on the use of force. This is because unjustified interference with, much less deliberate attacks against their shipping, would fall afoul (p.166) of the prohibition on the use of force and also because it could not possibly justify the requirement of specific necessity (p.149).

Conclusion

Switzerland’s and Sri Lanka’s determination of the existence of a state of war and the invocation of the law governing neutrality illustrate the continuing relevance of the Hague law governing neutrality. The reality of the ongoing inter-belligerent hostilities is that neither side has been adhering to the Charter framework. Nonetheless, the recognition by Switzerland and Sri Lanka of a state of war for purposes of invoking neutrality is quite distinct from the issue of any judgment about the legality of the war itself. At least in the case of Switzerland, this has been evidenced by its condemnation of the Israeli/USA attacks as a violation of international law.

This dual reality underscores the point that the consequences of an illegal war relating to both the determination of aggression and/or individual criminal responsibility remain unaffected by a recognition of the state of war. The mere fact that the UN may be unable to make a determination of who is the aggressor and who is the victim, does not mean third states do not make their own assessment of the same. Consequently, it is incorrect to suggest that the recognition of a state of war to invoke neutrality justifies or legitimizes an aggressor or is, ipso facto, inconsistent with a charter governed international order.

Indeed, the current conflict has been characterized by the US Secretary of Defense as a war. There have been legal commentators who concur that the hostilities have crossed the threshold of a war. Furthermore, in the deliberations accompanying the passage of UNSC Resolution 2817, France, Russia, China and Iran, all alluded to the ongoing “war”. Nonetheless, resolution 2817 confirms that the UN Charter does continue to govern inter-state relations even during a state of war.

The co-existence of a Charter-governed order and the law of neutrality reflects the fact that a neutral and belligerent state continue to be governed by the law of peace—this being the very basis for a neutral state’s entitlement to not be adversely affected by a conflict. This reflected the reality well over a century ago, when the Hague Conventions were first drafted. Today then, it is an even more unimpeachable proposition, given that the baseline understanding is no longer that peacetime legal regimes are automatically displaced by a state of war (see Mancini, pp. 993-995). Ultimately then, to not duly account for the Hague law governing neutrality is to risk rendering invisible the legal architecture which upholds the rights of all third parties who are not belligerents themselves.