The Legality of a Houthi Bab el-Mandeb Blockade under International Law
- Edmarverson A. Santos
- 8 hours ago
- 20 min read
Introduction
On 20 July 2026, Houthi authorities announced an immediate maritime blockade against Saudi Arabia. The public statement associated the measure with Bab el-Mandeb, yet it neither closed the strait to general navigation nor identified blockade coordinates, designated ports, exemptions, or enforcement procedures. The article accordingly examines a claimed Bab el-Mandeb blockade whose legal existence and validity remain to be established (Reuters, 2026a).
The legal consequences turn on the measure's actual scope. Preventing access to named Saudi Red Sea ports would resemble a conventional blockade. A prohibition covering every Saudi-flagged, Saudi-owned, Saudi-bound, or commercially associated vessel would be much wider, while exclusion of neutral traffic from Bab el-Mandeb would amount to a different operation altogether.
Legal capacity is the threshold issue. Blockade developed as a belligerent right in international armed conflict, whereas the Houthis are an organized non-state armed group. Common Article 3 binds parties to a non-international armed conflict while preserving their legal status; equal humanitarian duties do not confer belligerent powers against third states or neutral shipping (Geneva Conventions, 1949, common art. 3).
Assuming that threshold could be crossed, the announced measure would still have to satisfy blockade law. The San Remo Manual requires declaration, notification, defined geographic limits, effectiveness, and impartial application. It also addresses starvation and excessive civilian harm (San Remo Manual, 1994, paras 93-104). As a non-binding expert restatement, the Manual must be tested provision by provision against treaty law, state practice, and opinio juris.
Enforcement raises its own questions. Warning, visit and search, diversion, capture, condemnation, and attack are governed by different rules. A commercial connection with Saudi Arabia cannot, without further facts, justify either capture or attack against a merchant vessel.
The law of international straits imposes an independent constraint. UNCLOS protects continuous and expeditious transit passage and bars bordering states from hampering or suspending it (UNCLOS, 1982, arts 37-44). Those treaty duties belong to states rather than the Houthis, but they show why closing Bab el-Mandeb cannot be treated as the equivalent of blockading an enemy port.
The announcement did not, by itself, create an effective blockade. A narrowly drawn operation against specified Saudi Red Sea ports would present the most plausible legal case; a general closure of Bab el-Mandeb would not.
1. The Claimed Blockade and Its Factual Basis
The reported measure targeted commercial dealings with Saudi ports and threatened consequences for non-compliant vessels. Its wording and early implementation provide no evidence of a geographically delimited closure of Bab el-Mandeb.
1.1 The Announcement and Its Geographic Scope
The Houthi armed forces announced the measure on 20 July 2026 as retaliation for Saudi actions against Yemen. The declaration took immediate effect but omitted named ports, maritime coordinates, humanitarian exemptions, a termination date, and detailed enforcement procedures (Reuters, 2026a).
Further information appeared in a notice reportedly sent to shipping companies by the Houthi-controlled Humanitarian Operations Coordination Center. It instructed vessels not to load or discharge cargo at “any Saudi ports” from 12:01 GMT on 20 July. The notice warned that non-compliant vessels could face sanctions and might be targeted wherever they entered the operational reach of Houthi forces (Reuters, 2026b).
The notice reached beyond designated Saudi Red Sea ports. It addressed dealings with all Saudi ports and linked enforcement to the reach of Houthi weapons rather than to a defined maritime zone. A conventional blockade declaration ordinarily identifies the coast or ports concerned so that neutral shipping can understand the limits of the prohibition.
Neither document purported to close Bab el-Mandeb to every ship or aircraft. The strait matters operationally because traffic serving Saudi Red Sea ports may use it and Houthi forces operate from Yemen's western coast. Disruption along that route, however, is not the same as closure of the strait.
1.2 Vessels and Commercial Activity Covered
The shipping notice used port calls as its principal criterion. A vessel that loaded or discharged cargo at a Saudi port appeared to fall within the warning regardless of its flag, registration, ownership, charter, cargo, or crew. On that wording, even a neutral ship carrying civilian goods could face threatened measures because of an ordinary commercial call.
That category extends well beyond Saudi warships, naval auxiliaries, state vessels, and merchant ships supporting military operations. It also departs from the traditional object of blockade, which is entry to or departure from a defined enemy coast.
The phrase 'Saudi-linked shipping' hides legally important differences. Flag establishes nationality; ownership and operation may reveal commercial control; cargo and destination may affect liability to capture; and attack requires the vessel to qualify as a military objective or to meet another recognized naval-warfare ground. General economic association cannot replace those inquiries.
No public exemption covered medical vessels, humanitarian relief, passenger traffic, food shipments, or other essential civilian cargo. The notice likewise disclosed no process for contesting a classification or obtaining safe passage.
1.3 Declaration, Maritime Threat, or Effective Blockade
Earlier Houthi operations show that the group can locate and attack merchant shipping with missiles, drones, unmanned surface systems, small craft, and boarding teams. That record makes the warning credible, although it says little about whether the July measure was already operating as a blockade (United States Maritime Administration, 2026).
Commercial operators reacted cautiously. Two tankers carrying Saudi crude toward Asian markets turned back in the Red Sea instead of continuing through Bab el-Mandeb. Yanbu remained open for loading, and maritime authorities recorded no confirmed attack attributable to the new measure during its first 48 hours (Reuters, 2026b).
There was, at that point, no verified boarding, capture, compulsory diversion, mine deployment, or sustained kinetic enforcement under the July declaration. Rerouting demonstrated commercial concern, not effective control over ingress and egress.
The evidence supports the description of a threatened maritime interdiction regime rather than an effective blockade. It influenced shipping decisions, but neither Saudi port access nor navigation through Bab el-Mandeb had been brought under sustained Houthi control.
2. Bab el-Mandeb and the Law of International Straits
Bab el-Mandeb links the Red Sea and the Gulf of Aden and serves international navigation between maritime areas beyond territorial seas. Part III of UNCLOS governs passage through the strait (UNCLOS, 1982, art. 37).
2.1 The Strait’s Geographic and Legal Configuration
Yemen borders the eastern side of the strait, while Djibouti and Eritrea border its African side. Yemen’s Mayyun Island, also known as Perim Island, divides Bab el-Mandeb into two channels: the narrower Bab Iskander channel between the island and the Yemeni mainland, and the wider Dact el-Mayun channel to the west.
Article 38(1) removes an island-mainland channel from transit passage only when a seaward route through the high seas or an exclusive economic zone is similarly convenient in navigational and hydrographic terms. The western channel does not meet that jurisdictional condition because surrounding territorial seas extend across it. On that reading, transit passage applies throughout Bab el-Mandeb even though the two channels differ in depth, width, and ordinary use (Lott, 2021).
Coastal-state sovereignty over the waters, airspace, seabed, and subsoil remains intact. Article 34 subjects its exercise, however, to Part III and other applicable rules of international law (UNCLOS, 1982, arts 34 and 38).
2.2 Transit Passage and Its Legal Addressees
Transit passage entitles ships and aircraft to move through or over the strait continuously and expeditiously. Ships may use their normal mode of operation, while all transiting vessels and aircraft must proceed without delay and avoid activities unrelated to passage (UNCLOS, 1982, arts 38-39).
The bordering states retain regulatory authority over matters such as navigational safety, pollution, fishing, and customs. Their laws may neither discriminate among foreign vessels nor hamper, impair, or suspend transit passage (UNCLOS, 1982, arts 42 and 44).
UNCLOS assigns those powers and duties to states. Control of part of Yemen's coastline neither makes the Houthis a treaty party nor transfers Yemen's coastal-state authority to the group. Customary rules and IHL may bind Houthi forces on other grounds.
In Corfu Channel, the International Court of Justice recognized a customary peacetime right of innocent passage through straits used for international navigation (ICJ, 1949, p. 28). The later UNCLOS regime goes further by protecting overflight and normal-mode navigation. State practice gives substantial support to that broader regime, although the customary status of every detail of Part III is not beyond dispute.
2.3 Transit Passage During Armed Conflict
UNCLOS contains no rule suspending transit passage when armed conflict begins. The San Remo Manual accordingly treats the right as continuing for neutral and belligerent ships and aircraft, provided that transit remains continuous and expeditious and is not used for unrelated hostile operations (San Remo Manual, 1994, paras 27-30).
The strait also includes territorial waters of Djibouti and Eritrea, neither of which is made a party to the Saudi-Houthi hostilities by the announcement. Houthi control on the Yemeni shore cannot authorize operations in their waters or airspace. Security measures on Yemen's side, even if otherwise lawful, would not support closure of the whole strait.
3. The Legal Requirements of Naval Blockade
Customary international law supplies the principal rules of naval blockade. Their content emerges from treaty practice, prize decisions, state conduct, and official military manuals. The San Remo Manual offers the most coherent modern restatement, but it is not an independent source of binding law (San Remo Manual, 1994, paras 93-104).
3.1 Sources and Status of Blockade Law
Paragraph 4 of the 1856 Declaration of Paris states that a blockade binds other states only when a force sufficient to prevent access to the enemy coast makes it effective. The effectiveness requirement is widely accepted as customary international law (Declaration Respecting Maritime Law, 1856, para. 4).
Naval manuals and specialist writing also support declaration, notification, impartial enforcement, and preservation of access to neutral coasts. The unratified 1909 Declaration of London influenced those rules, but its provisions bind only to the extent that later state practice and opinio juris established them as custom.
The San Remo Manual carries these traditional rules into contemporary naval warfare. Its treatment of declaration, notification, effectiveness, and impartiality is broadly accepted. Paragraph 102(b), which compares expected civilian damage with the concrete and direct military advantage anticipated from the blockade, is more controversial as a statement of custom.
Most of this doctrine was developed for international armed conflict. Its application to a non-state armed group claiming powers against neutral shipping cannot be assumed.
3.2 Declaration, Notification, and Effectiveness
A declaration must be communicated to belligerent and neutral states. Under the San Remo formulation, it should state the commencement, duration, location, geographic extent, and the period allowed for neutral vessels to leave the blockaded coast. Cessation, extension, temporary lifting, and re-establishment likewise require notice (San Remo Manual, 1994, paras 93-94).
Neutral masters and flag states must be able to identify the affected coast and the conduct said to breach the blockade. A warning tied only to the geographic reach of weapons leaves those limits uncertain.
Effectiveness depends on operational reality rather than a prescribed formation of ships. Surveillance systems, aircraft, missiles, drones, mines, and remote platforms may all contribute; an enforcing force need not remain immediately outside the port. Each method of enforcement must itself comply with the applicable law.
Range and lethality are relevant, but neither proves control. The blockading force must maintain a credible capacity to detect and stop attempted ingress or egress. Sporadic attacks and rerouting caused by fear may disrupt trade without meeting that standard.
3.3 Impartiality and Geographic Limits
Impartiality requires comparable treatment of vessels from all states that attempt to enter or leave the blockaded area (San Remo Manual, 1994, para. 100). Medical and humanitarian exemptions are compatible with that rule; politically selective enforcement among otherwise comparable vessels is not.
The operation must remain tied to an identifiable enemy coast or port and may not obstruct access to neutral territory (San Remo Manual, 1994, para. 99). Enforcement can occur at some distance when military conditions demand it, but distance cannot enlarge the lawful object of the blockade.
These geographic limits separate a blockade of named enemy ports from a closure of an international strait or a campaign against vessels selected through an imprecise commercial association.
3.4 Humanitarian Limits on Blockade
Starvation of civilians as a method of warfare is prohibited. Article 54 of Additional Protocol I applies in international armed conflict, and Article 14 of Additional Protocol II applies in conflicts governed by that Protocol. Customary law extends the prohibition to both conflict classifications (Additional Protocol I, 1977, art. 54; Additional Protocol II, 1977, art. 14; Henckaerts and Doswald-Beck, 2005, rule 53).
Paragraphs 102-104 of the San Remo Manual bar a blockade directed solely at starving civilians or denying them objects essential to survival. If the population lacks adequate food or other essential supplies, passage must be allowed subject to inspection and impartial supervision; medical supplies are governed by corresponding technical arrangements (San Remo Manual, 1994, paras 102-104).
Purpose, evolving civilian conditions, and individual enforcement acts require separate assessments. A blockade can be unlawful from the outset, become unlawful as deprivation deepens, or be enforced through particular attacks that violate distinction, proportionality, precautions, or the special protection of medical and humanitarian vessels.
4. Can the Houthis Exercise Blockade Rights?
The central doctrinal difficulty arises before compliance is considered: blockade purports to alter the position of neutral states and vessels. International law has not clearly extended that external belligerent power to every non-state party to a NIAC.
4.1 Blockade and the Traditional Law of Belligerency
Classical international law distinguished rebellion, insurgency, and recognized belligerency. Recognition signaled that an internal conflict had reached a level at which the law of war and neutrality regulated relations with third states. It could give insurgents limited powers over neutral commerce, including blockade and prize enforcement, without treating them as a state (Lauterpacht, 1947).
Common Article 3 made minimum humanitarian rules applicable without recognition and expressly preserved the parties' legal status (Geneva Conventions, 1949, common art. 3). That development allowed states to accept humanitarian regulation without conceding combatant immunity, prize jurisdiction, or powers over neutral shipping. Formal recognition of belligerency consequently became rare.
4.2 NIAC, Belligerent Equality, and Neutral Rights
Equality of belligerents requires applicable IHL to bind both sides regardless of the legality of their cause or their status under domestic law. A government cannot invoke the rebellious character of its opponent as a reason to disregard humanitarian restraints.
The principle says nothing comparable about international legal personality. Common Article 3 and customary IHL do not give an armed group sovereign powers, treaty rights, combatant privilege, prize jurisdiction, or regulatory authority over neutral vessels. Humanitarian obligations may be symmetrical while external legal capacities remain different.
Houthi forces remain bound by rules protecting civilians and civilian shipping even if they cannot impose a blockade on neutral commerce. The duty to comply with those rules is not evidence of the claimed belligerent power.
4.3 Conflict Classification and Houthi Legal Capacity
The armed conflict between the Houthis and the Yemeni government is ordinarily classified as non-international because organized state and non-state forces have engaged in sufficiently intense hostilities. Under the ICRC's support-based approach, a foreign state may become a party to that NIAC when coordinated support makes a direct and effective contribution to the collective conduct of hostilities. The approach is influential, though not universally accepted as the exclusive test for co-party status (International Committee of the Red Cross, 2024).
Cross-border fighting between Saudi Arabia and the Houthis does not become international merely because it crosses a state boundary. Hostilities between a state and an organized non-state group may remain a NIAC where the organization and intensity thresholds are met (ICTY, 1995, para. 70).
Conflict classification and state responsibility use different control tests. The ICTY Appeals Chamber applied overall control to determine whether an organized armed group acted on behalf of a foreign state, requiring involvement beyond financing and equipping and extending to the planning and supervision of military operations (ICTY, 1999, paras 131 and 145-146). Article 8 of the Articles on State Responsibility and the ICJ's effective-control test instead address attribution of particular conduct through instructions, direction, or control over the operation in question (ILC, 2001, art. 8; ICJ, 1986, para. 115). Success under one test does not establish the other.
Territorial administration, coastal control, ports, and weapons give the Houthis practical maritime capacity. They do not transform the group into a state, transfer Yemen's treaty powers, or create jurisdiction over neutral shipping.
4.4 The Strongest Competing Positions
A functional case can be made for limited maritime powers where an organized armed group controls coastline and possesses the means to conduct sustained naval operations. On that view, denying any blockade capacity while applying blockade-related humanitarian restraints creates a mismatch between operational reality and legal status.
Neutral rights make that argument difficult to sustain. State practice does not clearly permit non-state parties to NIACs to impose blockade duties on neutral vessels, seize neutral merchant ships, or exercise prize jurisdiction opposable to third states. Historically, those powers depended on state belligerency or recognition of belligerency, and modern scholarship continues to treat their use in NIACs as unsettled (Lauterpacht, 1947; Fink, 2023). The San Remo Manual, drafted for international armed conflict at sea, does not fill the gap (San Remo Manual, 1994, para. 1).
The available law supports Houthi attacks on lawful military objectives subject to IHL, but not an internationally binding blockade of neutral commerce based only on territorial control or belligerent equality. Recognized belligerency or clearer customary practice would be needed. Attribution of a particular operation to a state could alter responsibility or classification; it would not create a separate Houthi entitlement (Fink, 2023).
5. Applying Blockade Law to the Claimed Measure
For the purpose of applying the substantive rules, this section assumes arguendo that the Houthis could invoke blockade law. The assumption leaves unresolved the absence of clearly established non-state authority over neutral shipping.
5.1 Declaration and Notification
The notice took effect immediately and prohibited loading or discharging cargo at 'any Saudi ports.' It gave no termination date, blockaded coastline, coordinates, departure period for neutral vessels, humanitarian exemptions, inspection arrangements, or safe-passage procedure (Reuters, 2026b).
That level of uncertainty is incompatible with a blockade opposable to neutral shipping. Masters and flag states could not identify a delimited coast or the precise conduct said to constitute breach. A threat enforceable wherever a vessel enters Houthi operational range supplies no ascertainable boundary, and neutral vessels without sufficiently precise actual notice could not lawfully be treated as blockade runners (San Remo Manual, 1994, paras 93-96).
5.2 Operational Effectiveness
Coastal positions, surveillance, missiles, drones, small craft, and earlier boarding operations make Houthi threats credible. Effectiveness, however, requires continuing control over access to the coast said to be blockaded.
A claim covering 'any Saudi ports' cannot be reconciled with the demonstrated capability. Saudi Arabia has ports on the Red Sea and Persian Gulf, and the Houthis have shown no capacity to control access to all of them. Tanker rerouting showed perceived danger, while continued loading at Saudi Red Sea ports and the absence of verified enforcement under the new notice pointed away from an effective blockade (Reuters, 2026b).
5.3 Neutral Shipping and Commercial Links
The notice selected vessels because of commercial calls at Saudi ports. Blockade and targeting law use more exact classifications.
Flag, ownership, registration, charter, cargo, destination, control, and military use answer different legal questions. A neutral vessel may be captured for breach of a lawful blockade, contraband carriage, enemy control, or unneutral service. Attack ordinarily requires military-objective status or clear resistance to lawful capture after warning (San Remo Manual, 1994, paras 112-121).
A Saudi port call, civilian cargo, or a commercial relationship with a Saudi entity cannot establish those grounds without additional evidence. Describing the ship as 'Saudi-linked' avoids the classification that the law requires.
5.4 Capture and Prize Adjudication
Visit and search, diversion, capture, confiscation, and destruction have different legal consequences. Suspected blockade breach normally leads to capture and adjudication. Prize proceedings then determine whether the vessel or cargo was lawfully seized and whether condemnation is justified.
The Houthis also face an institutional problem. Without state authority or recognized belligerency, a Houthi tribunal has no established standing as an internationally competent prize court, and neutral states would not be bound to recognize its confiscation orders. Destruction is subject to stricter conditions, including protection of passengers and crew (San Remo Manual, 1994, paras 138-152; Fink, 2023).
5.5 Ports, Military Shipping, and Strait Closure
The notice brings together operations that international law treats differently. A blockade of named Saudi Red Sea ports would fall within traditional blockade doctrine only if the Houthis had the requisite legal capacity and complied with notification, effectiveness, impartiality, and humanitarian rules.
Saudi warships and naval auxiliaries are governed by naval targeting law. Merchant vessels supporting military operations may be captured or attacked only under the specific rules on enemy character, military contribution, contraband, or resistance to capture.
A general closure of Bab el-Mandeb would have the weakest legal basis. It would reach beyond access to enemy ports, interfere with neutral transit, and affect waters of Djibouti and Eritrea. The reported notice and early enforcement record satisfy neither the legal nor factual requirements of a blockade.
6. Humanitarian Limits and Unlawful Enforcement
IHL limits the purpose, effects, and enforcement of a blockade regardless of who claims the power to impose it. Formal compliance with declaration and effectiveness rules would not cure starvation, arbitrary obstruction of relief, or unlawful attacks on merchant shipping.
6.1 Starvation and Essential Civilian Supplies
Starvation of civilians as a method of warfare is prohibited in international and non-international armed conflict. Article 54 of Additional Protocol I regulates IAC, Article 14 of Additional Protocol II applies in conflicts governed by that Protocol, and customary law covers both classifications (Additional Protocol I, 1977, art. 54; Additional Protocol II, 1977, art. 14; Henckaerts and Doswald-Beck, 2005, rule 53).
Trade disruption and higher transport costs are not enough to prove starvation. Relevant evidence would include the operation's purpose, the goods obstructed, civilian dependence, alternative supply routes, and an intent to use deprivation of food, water, medicine, fuel, or comparable essentials as a method of warfare.
6.2 Humanitarian Relief and Protected Shipping
Relief operations are generally subject to the consent and control of the relevant party, but consent is not absolute. When civilians lack essential supplies, a humanitarian and impartial relief operation conducted without adverse distinction may not be refused arbitrarily (Additional Protocol II, 1977, art. 18(2); Henckaerts and Doswald-Beck, 2005, rule 55).
Reasonable controls may include cargo inspection, prescribed routes, recipient verification, and measures against diversion. They cannot be used as a pretext to prevent necessary relief. Medical vessels and humanitarian shipping retain protection unless their conduct satisfies the conditions for loss of that protection.
6.3 Attacks on Commercial Vessels
Merchant vessels are civilian objects unless they meet the customary military-objective test, codified for IAC in Article 52(2) of Additional Protocol I. Their nature, location, purpose, or use must make an effective contribution to military action, and their destruction, capture, or neutralization must offer a definite military advantage in the circumstances (Additional Protocol I, 1977, art. 52(2); Henckaerts and Doswald-Beck, 2005, rule 8).
Suspected blockade breach or contraband carriage normally calls for interception and capture, not immediate attack. Missiles, drones, mines, and boarding operations remain subject to distinction, proportionality, verification, feasible precautions, and warning where circumstances permit. Ordinary navigation, delayed communications, and commercial trade with Saudi Arabia do not amount to resistance to capture.
Shipwrecked persons and others hors de combat must be respected and protected. Parties must, where circumstances permit, search for, collect, and evacuate the wounded, sick, and shipwrecked (Henckaerts and Doswald-Beck, 2005, rules 47 and 109).
6.4 Responsibility and Legal Consequences
Invalid blockade, unlawful attack, and war crime are different legal findings. Criminal responsibility requires the elements of a recognized offence, a nexus with armed conflict, the applicable mental element, and a jurisdictional basis; breach of a blockade or targeting rule alone is insufficient.
Enforcement attacks of sufficient scale and effect may engage Article 51 of the United Nations Charter. International law remains divided on whether self-defense may be exercised against a non-state armed group when its attacks are not attributable to another state (UN Charter, 1945, art. 51; ICJ, 2004, para. 139).
Weapons, financing, intelligence, training, or political support do not alone attribute Houthi conduct to another state. Article 8 requires instructions, direction, or control over the operation concerned, while Article 11 covers conduct clearly acknowledged and adopted by a state as its own (ILC, 2001, arts 8 and 11; ICJ, 1986, para. 115).
7. Is the Bab el-Mandeb Blockade Lawful?
The announced measure is not a lawful Bab el-Mandeb blockade on the facts presently verified. It lacks an established legal basis for binding neutral shipping and fails on geographic definition, notice, effectiveness, and enforcement safeguards.
7.1 A Blockade of Saudi Red Sea Ports
A measure confined to named Saudi Red Sea ports would offer the most plausible blockade claim. A state belligerent could restrict entry and departure if it declared and notified the blockade, enforced it effectively and impartially, and observed humanitarian law.
The Houthis do not occupy that legal position. International law provides no clear authority for an unrecognized non-state party to a NIAC to impose blockade duties on neutral states and vessels. Territorial control and military capability show capacity to act, not prize or blockade authority opposable to third states.
The notice would remain defective even if that authority were assumed. Its reference to 'any Saudi ports' supplies neither a defined coastline nor a period for neutral departure, and the record shows no sustained prevention of access. Precision, notification, and effectiveness are all missing (San Remo Manual, 1994, paras 93-100).
7.2 Interdiction of Saudi Military Shipping
Saudi warships fall under naval targeting law rather than blockade doctrine. Naval auxiliaries and merchant vessels performing military functions may also become military objectives when their nature, purpose, location, or use makes an effective contribution to military action.
Every attack remains subject to distinction, proportionality, and feasible precautions. Operations in the territorial waters of Djibouti or Eritrea would also violate their sovereignty. A lawful strike on an individual military objective would say nothing about the validity of the broader blockade claim.
7.3 Attacks on Saudi-Linked Merchant Vessels
Merchant vessels remain civilian objects unless the military-objective test is met. Saudi ownership, registration, destination, charter, and commercial association may contribute evidence, but no single commercial connection makes a vessel targetable.
Weapons carriage, military intelligence support, naval auxiliary functions, or another effective contribution to military action may justify attack when the remaining targeting conditions are satisfied. A neutral ship carrying ordinary civilian goods to a Saudi port retains civilian protection.
Contraband carriage or attempted breach of a lawful blockade would ordinarily justify interception and prize adjudication. Immediate destruction requires a narrower and independent legal basis (San Remo Manual, 1994, paras 67-69, 98 and 118-121).
7.4 Closure of Bab el-Mandeb to General Navigation
Blockade law supplies no defensible basis for an indiscriminate closure of Bab el-Mandeb to neutral ships and aircraft. Its object is access to an enemy coast or port, not exclusion from neutral territory or the strait as a whole.
UNCLOS protects continuous and expeditious transit and prohibits bordering states from hampering or suspending it (UNCLOS, 1982, arts 37-44). The Houthis are neither a treaty party nor a coastal state entitled to exercise Yemen's regulatory powers. Control of the Yemeni shore gives them no authority in the territorial waters of Djibouti or Eritrea.
7.5 Overall Legal Conclusion
The record supports a clear result. The notice lacks the precision, notification, effectiveness, impartiality, and humanitarian arrangements required for blockade, and ordinary commercial association cannot make a merchant vessel liable to attack.
Uncertainty remains over whether any non-state armed group may exercise blockade rights against neutral shipping in a NIAC. The better view requires recognized belligerency or clearer customary practice. Overall control by a foreign state may affect conflict classification, and effective control over a particular operation may establish attribution; neither test creates an independent Houthi blockade power (ICTY, 1999, paras 131 and 145-146; ICJ, 1986, para. 115).
That doctrinal uncertainty does not validate the present measure. Individual attacks on Saudi military objectives may be lawful under naval targeting rules, but they cannot support a general closure of the strait or attacks on merchant vessels chosen only for Saudi commercial links.
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Conclusion
The Houthis cannot lawfully enforce a general blockade of Bab el-Mandeb on the record examined. Their announcement created a credible threat and changed some shipping decisions, but it neither defined a lawful blockade zone nor established sustained control over access to the ports concerned (Reuters, 2026b).
The deeper obstacle is legal authority. IHL binds organized armed groups without granting them every belligerent power that international law accords to states against neutrals. Current law gives no clear basis for an unrecognized non-state party to a NIAC to impose blockade duties, exercise internationally opposable prize jurisdiction, or extinguish neutral navigation rights (Geneva Conventions, 1949, common art. 3).
A future assessment could change if recognized belligerency, clearer customary practice, or a properly declared and effective blockade altered the legal or factual position. Attribution or overall control might affect responsibility and conflict classification, but neither would itself turn the Houthis into a coastal state or confer an independent right to close Bab el-Mandeb. Operations against specific Saudi military objectives remain governed by naval targeting law, not by the defective general blockade claim.
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