The End of Unconditional Transit Passage? Hormuz and the Reconstruction of Straits Law-Dr. Mohammad Mehdi Seyed Nasseri & Zahra Maleki Rad

Dr. Mohammad Mehdi Seyed Nasseri - Lecturer and Researcher in Children's Rights & Zahra Maleki Rad - Ph.D. Student of Public International Law, Faculty of Law, University of Qom
2026/07/04

In contemporary international law, certain concepts have come to be regarded as so self-evident that they are rarely subjected to fundamental reconsideration. “Transit passage through international straits” is one such concepts; a rule which, in its classical understanding, rests upon a seemingly simple yet profoundly determinative assumption: that straits must remain neutral, even when the surrounding world is engulfed in armed conflict. This legal presumption has, over past decades, become so deeply entrenched in the law of the sea that it appears almost natural and beyond contestation. Yet recent developments in the security environment of the Persian Gulf most notably the large-scale U.S.–Israeli war against Iran have challenged this assumption at a foundational level. What has emerged is not merely a transient geopolitical crisis, but rather the emergence of a new legal condition in which the Strait of Hormuz can no longer be meaningfully understood within the classical framework of an “ordinary international waterway.” What we are witnessing is not a matter of interpretative disagreement, but a paradigmatic rupture in the law governing international straits. This post argues that, in light of the structural militarization of the region and the active use of the Strait as a logistical instrument in an armed campaign, the notion of unconditional transit passage is no longer tenable. It must instead be reconceptualized within a new framework grounded in the principles of necessity, proportionality, and the prohibition of abuse of rights. Within this framework, even Iran’s decision to regulate or restrict the passage of certain vessels should not be construed as a “closure” of the Strait, but rather assessed in light of the inherent right of self-defense under Article 51 of the UN Charter and the sovereign prerogatives of the coastal State within its territorial sea.

The Collapse of the Assumption of Neutrality in the Classical Law of Straits

The legal regime governing international straits, particularly as codified in the 1982 United Nations Convention on the Law of the Sea (UNCLOS), is built upon a subtle yet crucial distinction: that between “innocent passage” and “transit passage.” The purpose of this regime is to ensure the uninterrupted flow of navigation through geographically strategic chokepoints without undermining the sovereignty of coastal States. However, this entire legal architecture rests upon an implicit assumption: that straits are not structurally implicated in armed conflict as instruments of warfare. In other words, the law of the sea was never designed for a situation in which a strait itself becomes part of the “operational chain of war.” Recent experience in the Persian Gulf has fundamentally disrupted this assumption. For the first time, a major international strait has been used not merely as a route for global commerce, but as an operational corridor for a coordinated military campaign one involving direct attacks, extensive logistical support, the movement of military equipment, and the use of maritime routes to sustain armed operations against a coastal State. Under such conditions, it is no longer meaningful to speak of the “functional neutrality” of the Strait. Its very function has been transformed. The Strait has shifted from being a connective passageway to becoming an operational infrastructure of warfare. This transformation carries a critical legal implication: when the object of a legal regime changes, the interpretation of the rules governing it must necessarily be reconsidered.

Transit Passage and the Problem of Abuse of Rights

One of the foundational principles of international law is the prohibition of abuse of rights. No right even one that appears absolute may be exercised in a manner that distorts its purpose or transforms it into a vehicle for violating other fundamental norms of international law, particularly the prohibition on the use of force under Article 2(4) of the UN Charter. Against this backdrop, a fundamental question arises: can the right of transit passage be invoked in a manner that effectively facilitates military operations against a coastal State? If the answer is in the affirmative, then transit passage ceases to be a mechanism facilitating peaceful navigation and becomes, instead, a legally sanctioned instrument of warfare. This marks the precise point at which the existing legal order encounters an internal contradiction. In the present context, the use of the Strait of Hormuz as an operational support route for military actions against Iran constitutes a paradigmatic example of this tension. Under such circumstances, the insistence on “unconditional passage” is not merely an expansive interpretation of the law of the sea, but reflects a deeper disregard for the systemic coherence of international law as a whole.

Reinterpreting Article 51: Self-Defense in the Maritime Domain

In confronting this situation, it is necessary to return to one of the most fundamental rules of international law: the inherent right of self-defense. Article 51 of the UN Charter is not a narrow exception, but a structural norm that enables the rebalancing of sovereignty and security in the face of armed threats. Yet in classical legal discourse, its application has been largely confined to territorial or aerial contexts, with insufficient attention paid to its maritime dimensions. In contexts such as the Persian Gulf where the boundary between “transit space” and “operational theater” is effectively erased it is neither realistic nor legally coherent to expect the coastal State to remain a passive observer of hostile uses of adjacent maritime routes. Accordingly, measures such as regulating the passage of vessels associated with hostile parties, provided they meet the requirements of necessity and proportionality, may be justified within the framework of self-defense. Such measures should not be viewed as violations of international law, but as lawful acts aimed at preserving the survival and territorial integrity of the coastal State. This reinterpretation does not negate the regime of transit passage; rather, it acknowledges that no legal regime can operate in absolute terms within the context of structural insecurity and militarized use of maritime infrastructure.

Structural Militarization of the Persian Gulf and the Transformation of the Strait’s Legal Character

To fully grasp the transformation of the legal status of the Strait of Hormuz, one must move beyond episodic events and consider the entrenched security architecture of the region. What has emerged in the Persian Gulf is not merely a scattered presence of foreign forces, but a coherent, sustained, and strategically oriented network of extra-regional military power that directly shapes the region’s legal and security equilibrium. Military installations in Bahrain, Qatar, the United Arab Emirates, Saudi Arabia, and Kuwait, coupled with extensive U.S. naval and aerial presence, have created a security architecture whose function extends beyond defense or deterrence. In practice, this network enables the projection of offensive force against a specific coastal State namely Iran within extremely short timeframes. In such a context, the Strait of Hormuz is no longer merely a geographical passage; it is embedded within a militarized ecosystem. This ecosystem erases the boundary between peaceful navigation and armed conflict, producing a condition that may be described as one of “permanent quasi-conflict.” Within classical international law, the concept of an “international strait” is predicated on the neutrality of its surrounding environment. However, when that environment becomes structurally militarized, the Strait itself cannot remain unaffected. A strait situated amidst active military bases and continuous operations by foreign powers can no longer be meaningfully regarded as a neutral passageway. Functionally, the Strait of Hormuz approaches what may be termed an “extension of the operational theater.” This shift carries direct legal consequences: where the surrounding environment is characterized by hostility and militarization, the interpretation of the rules governing passage cannot be divorced from that reality.

The Erosion of Functional Neutrality and the Reconfiguration of International Straits

In the law of the sea, an “international strait” is not merely a geographical concept, but a functional legal institution. It presupposes that such straits fulfill three core characteristics:

• serving as connectors between two bodies of international waters;
• facilitating peaceful, non-military navigation;
• and not functioning as instruments of coercion or force.

However, when one side of a strait becomes effectively integrated into the operational infrastructure of an external military power capable of projecting force against a specific State, these characteristics are simultaneously undermined. Under such conditions, the strait ceases to be merely a passageway and becomes part of an asymmetrical military power structure. This transformation alters its legal character. Consequently, the insistence on preserving the classical notion of “unconditional transit passage” in such a context reflects a form of legal abstraction detached from structural realities. If international law is to retain its normative credibility, it cannot remain indifferent to such transformations. Legal rules preserve their legitimacy only insofar as they adapt to structural realities, rather than resisting them through rigid conceptual formalism.

Rethinking Unconditional Passage

One of the central theoretical challenges in this debate is the concept of “unconditional passage.” While traditionally understood as a guarantee of global navigational freedom, this freedom was never designed to be absolute or immune from limitation. Even within the framework of UNCLOS, transit passage is conditioned upon the absence of threats or use of force against the sovereignty of the coastal State. In other words, the right itself contains inherent limitations. The issue becomes significantly more complex when passage is no longer a neutral commercial activity, but part of a coordinated military operation. In such cases, “passage” transforms into a strategic act within the framework of armed conflict. This leads to a fundamental question: can international law continue to defend the right of unconditional passage when that very passage is instrumental in facilitating an armed attack? A negative answer does not entail the rejection of navigational freedom; rather, it reflects the recognition that no freedom can be exercised in a manner that undermines the very legal order from which it derives.

Iran and the Logic of Self-Defense in the Maritime Domain

Within this analytical framework, Iran’s regulation of vessels associated with hostile parties must be reassessed through the lens of self-defense. In international law, self-defense is not confined to terrestrial military responses; it is a structural right aimed at preserving the existence and integrity of the State across all domains, including maritime space. Where a State faces an existential threat not merely hypothetical but manifested through concrete military operations it cannot reasonably be expected to remain entirely passive with respect to the routes through which that threat is projected. Here, the key criterion is proportionality. Defensive measures must be:

• directed at a specific threat;
• temporary in nature;
• and calibrated in proportion to the intensity of the threat.

Within this framework, regulating the passage of vessels linked to military operations against Iran does not violate international law; rather, it applies it in response to the realities of an armed threat. The foregoing analysis leads to a fundamental conclusion: the law governing international straits is undergoing a normative transition. This transition may be articulated along three dimensions:

• from presumed neutrality to conditional neutrality;
• from absolute transit rights to condition-based passage;
• from static law of the sea to regionally grounded security frameworks.

What is emerging is a new doctrinal orientation that may be described as a “security-oriented law of the sea.” Within this framework, freedom of navigation remains a foundational principle but not at the expense of ignoring security realities, nor in contradiction with the right of coastal States to survival and self-defense.

The Strait of Hormuz as a Turning Point in International Law

Today, the Strait of Hormuz is not merely a geographical chokepoint; it is a legal laboratory for testing the capacity of international law to respond to the realities of modern warfare. If international law is to avoid normative erosion, it must be capable of balancing three principles: freedom of navigation; security of coastal States; and the prohibition of abuse of legal structures. Ignoring any of these elements creates a structural imbalance that ultimately threatens the legitimacy of the entire system. Within this context, the Strait of Hormuz can no longer be considered an “ordinary” waterway, because the conditions that sustained such ordinariness no longer exist.

Call for Action: The law of the sea must recalibrate the balance between absolute freedom of passage and the imperatives of security under conditions of structural conflict; failing this, its rules risk evolving from instruments of restraint into mechanisms for the reproduction of violence.