Iran\u2019s attacks on neutral shipping and potential mining of the Strait of Hormuz violate both the law of the sea and the law of armed conflict\u2014and reveal how difficult those rules are to enforce in practice.<\/p>\n
The Strait of Hormuz<\/a> \u2014 a narrow chokepoint through which roughly 20 percent of the world\u2019s oil transits \u2014 is now an active conflict zone. Iranian forces have struck<\/a> multiple neutral merchant vessels and may be laying naval mines in the Strait, threatening<\/a> one of the most important shipping routes in the global economy.<\/p>\n Secretary of Defense Pete Hegseth has told<\/a> the world that \u201cwe don\u2019t need to worry about it.\u201d\u00a0 I disagree\u2014the security situation in the Strait is a source of immense worry, is acutely dangerous, and there is no easy fix. What\u2019s more, as I discuss below, the U.S. Navy\u2019s very recent decommissioning<\/a> of an entire class of minesweepers, without an effective ready replacement, makes an already precarious situation worse.\u00a0<\/p>\n The Strait\u2019s unique geography<\/a> also provides a textbook case of asymmetric warfare<\/a> that favors Iran; a naval mine or drone costing thousands can cause billions of dollars in economic or physical damage.\u00a0 And the mere perception of such a threat is enough to shut the Strait down indefinitely.\u00a0 During my own transits through the Strait as a naval officer aboard the aircraft carrier USS Constellation<\/a>, the narrow geography and proximity of Iranian territory were impossible to ignore. Even in peacetime, we took significant force protection measures with helicopters airborne and aircraft on alert as ships passed through.<\/p>\n And today we are in far more dangerous times.<\/p>\n What\u2019s more, there are reports<\/a> that Iran may already be mining the Strait, a significant escalation that could shut down one of the world\u2019s most critical shipping lanes, depending on the extent of the mining.\u00a0 Any attempts to demine the Strait and engage in defensive mine countermeasures will be difficult, if not near impossible, during a raging armed conflict.\u00a0 In the interim, maritime insurance rates are skyrocketing,<\/a> fuel prices are rising<\/a>, and merchant vessels laden with oil, gas, and fertilizer are staying clear of the Strait of Hormuz until their physical security can be guaranteed.\u00a0<\/p>\n Below, I address the key legal and operational questions that will define how the conflict over the Strait unfolds \u2014 and how international law constrains (or fails to constrain) Iran\u2019s actions.<\/p>\n What law governs maritime shipping through the Strait of Hormuz?<\/strong><\/p>\n The Strait of Hormuz is an international strait within the meaning of Article 37<\/a> of the UN Convention on the Law of the Sea (UNCLOS), which applies to straits \u201cused for international navigation between one part of the high seas or an exclusive economic zone and another part of the high seas or an exclusive economic zone.\u201d\u00a0 The outbreak of hostilities does not necessarily <\/a>suspend UNCLOS. \u00a0While the Strait of Hormuz is bordered by Iran to the north and Oman to the south, it is legally an international strait.\u00a0 Iran does not own the Strait of Hormuz, but it can effectively control maritime movement through the Strait based on its physical proximity.\u00a0 The Strait of Hormuz is legally distinct from the Turkish Straits linking the Mediterranean Sea with the Black Sea\u2014a key waterway in the Russia-Ukraine War.\u00a0 The Turkish Straits are governed by the Montreux Convention<\/a>, where Turkey has special legal authorities to regulate maritime traffic.\u00a0\u00a0<\/p>\n In the Strait of Hormuz,\u00a0 the right of transit passage<\/a> is afforded to all ships and aircraft that transit the strait, a permissive legal right that \u201cshall not be impeded\u201d\u2014even in times of war.\u00a0 All vessels and aircraft\u2014military and civilian\u2014have the legal prerogative to exercise the right of transit passage through the Strait of Hormuz, provided that these ships and aircraft proceed without delay<\/a> through the Strait of Hormuz, transit in their normal modes of operation, and refrain from using force against any nation bordering the Strait.\u00a0 Although Israel, Iran, and the United States are not parties<\/a> to UNCLOS, the transit-passage regime for international straits is widely regarded<\/a> as customary international law and binding on all States. Iran\u2019s actions to block the strait are contrary to both the letter and spirit of UNCLOS and applicable customary international law.<\/p>\n What are the challenges in transiting the Strait of Hormuz?<\/strong><\/p>\n Practically, the Strait of Hormuz is the only way to get oil, natural gas, fertilizer, and other goods from the Persian Gulf to international markets. Geographically, the Strait of Hormuz is extraordinarily narrow<\/a> in parts, with just 20 miles separating Iran from Oman at one point in the Strait.\u00a0 Naval officers and civilian mariners are rightfully wary of running aground\u2014a real concern for heavily-laden oil tankers and merchant vessels. And there are just two narrow corridors within the Strait itself for entering and exiting the Persian Gulf, thus making it exceedingly easy to identify, track, and target any vessel that transits the Strait.\u00a0\u00a0<\/p>\n While there are reports of 2,500 U.S. Marines<\/a> deploying to the region, a successful occupation of the southern tip of Iran bordering the Strait will not by itself immunize shipping from threats.\u00a0 And such an amphibious landing would be incredibly dangerous.\u00a0 Iran has already demonstrated the capacity to launch Shaheed drones<\/a> \u2014 with a range of 1,000 miles<\/a> \u2014 from virtually anywhere in Iran.\u00a0 The drone threat makes it difficult \u2014 if not impossible \u2014 to guarantee safe passage through the Strait within the foreseeable future.\u00a0\u00a0<\/p>\n Are Iranian actions violating international law? Where do things stand?<\/strong><\/p>\n Yes.\u00a0 Reports indicate that Iran has targeted civilian merchant vessels from Thailand, Japan, and the Marshall Islands; up to 16 civilian vessels<\/a> have been struck in total. Crewmembers and the vessels themselves are neutral \u2014 not belligerents \u2014 to the armed conflict with Iran.\u00a0 These Iranian strikes unlawfully target neutral, civilian objects and violate the fundamental principle of distinguishing<\/a> between civilian and military objectives under international humanitarian law. To be sure, there are key questions about the legality of the underlying legal justification for the war with Iran, as Kate Brannen, Tess Bridgman, and Ryan Goodman at Just Security<\/a> have posed, but the attacks on civilian merchant vessels are clearly unlawful.<\/p>\n Does Iran have the capacity to mine the Strait of Hormuz?<\/strong><\/p>\n Yes, and Iran possesses numerous naval mine variants<\/a> that could be used.\u00a0 According to the U.S. Defense Intelligence Agency, Iran has 5,000 naval mines<\/a> in its arsenal and has likely planned for such a scenario for decades.\u00a0 In 1988, a U.S. Navy vessel, the USS Samuel B. Roberts, struck a mine<\/a> in the Persian Gulf laid by Iran, snapping<\/a> the warship\u2019s keel and nearly sinking the vessel. Naval mining technology has gotten much more sophisticated since that tragic incident.\u00a0 And the Strait of Hormuz is just 200 feet deep<\/a> at its narrowest point, plenty shallow to lay a minefield to halt or throttle traffic.\u00a0<\/p>\n Is mining the Strait of Hormuz lawful?<\/strong><\/p>\n No.\u00a0 While naval mining is not unlawful per se<\/a>, placing mines in an international strait in a manner that effectively denies transit passage to neutral shipping is widely understood to violate both the law of naval warfare and the law of the sea.<\/p>\n Indeed, one of the earliest international humanitarian law treaties, the 1907 Hague VIII Convention<\/a> on the \u201cLaying of Automatic Submarine Contact Mines,\u201d was negotiated in response to the widespread and destructive naval mining that took place in the Russo-Japanese War, which killed hundreds of civilians well after the war\u2019s hostilities.\u00a0 Hague VIII specifically prohibits the \u201clay[ing] of contact mines off the coast and ports of the enemy with the sole object of intercepting commercial shipping.\u201d And Hague VIII<\/a> specifies that unanchored contact mines (which Iran possesses<\/a>) must become harmless within one hour after loss of control over them.\u00a0 Anchored mines must become harmless as soon as they are broken from their moorings.\u00a0\u00a0<\/p>\n In theory, a belligerent power may lawfully employ naval mines in an armed conflict, but mine placement in the Strait of Hormuz is illegal because there is no alternative convenient or commercially acceptable route available to neutral merchant shipping.\u00a0 The San Remo Manual on International Law Applicable to Armed Conflicts at Sea<\/a> emphasizes that belligerents may not mine international straits in a manner that effectively blocks neutral transit.\u00a0 Here is the influential Newport Manual on the Law of Naval Warfare<\/a>\u2019s discussion on mining\u00a0 straits during an active armed conflict:<\/p>\n Mining of a belligerent\u2019s own waters within a strait where the right of transit passage or non-suspendable innocent passage applies . . . is lawful provided that an alternative convenient or commercially acceptable route is available to neutral merchant shipping.<\/p>\n The U.S. Navy\u2019s Handbook on the Law of Naval Operations<\/a> reiterates this prohibition, stating that naval mines may not be placed in a manner to deny transit passage of international straits.\u00a0 Furthermore, there is a general obligation for States to take feasible precautions<\/a> under the law of war\u2014this applies when using naval mines; every possible precaution must be taken for the security of peaceful shipping.\u00a0<\/p>\n What are the Operational Risks in \u201cDemining\u201d the Strait of Hormuz?<\/strong><\/p>\n Many. \u00a0 Once an area has been mined, it is often virtually impossible to guarantee that it has been fully demined.\u00a0 An oil tanker explosion with a naval mine would be an environmental disaster that would further halt shipping.\u00a0 Following the armed conflict, Iran would have an affirmative obligation under Hague VIII to remove its own mines. Still, commercial shippers would have to trust Iran that this has taken place. \u00a0 And removing mines is notoriously difficult.\u00a0 Since 1997, a multinational naval mine clearance and ordnance disposal operation has been conducted<\/a> in the Baltic Sea to clear and destroy an estimated 160,000 mines from the First and Second World Wars, and just 20% have been removed or destroyed.\u00a0<\/p>\n Complicating matters, at this very moment, the U.S. Navy is retiring<\/a> its four Avenger-class minesweepers previously homeported in the Middle East and moving toward a different strategy<\/a>. The new strategy for mine countermeasures is untested and focuses on using the Littoral Combat Ship (LCS) in combination with helicopter support, drones, and Explosive Ordnance Disposal<\/a> personnel.\u00a0 In an apparently shortsighted move, just one month before the Iran conflict began, the four Avenger-class<\/a> minesweeper vessels left<\/a> their home port of Bahrain to be decommissioned and scrapped in the Philadelphia Naval Shipyard.\u00a0 \u00a0 The U.S. Navy acknowledges<\/a> that the LCS \u201cwill always struggle to achieve the same level of Mine Countermeasure proficiency\u201d as dedicated minesweepers.\u00a0 It remains to be seen whether the combination of LCS, helicopters, Explosive Ordnance Disposal, and Navy-trained dolphins<\/a> (with natural sonar capability) can fill the gap left behind by these departed minesweepers.\u00a0 Finding naval mines in an international strait is already notoriously difficult, particularly in an international strait that has so much existing debris that camouflages the existence of mines.<\/p>\n Can U.S. Navy vessels escort civilian vessels transiting the Strait?<\/strong><\/p>\n Yes, but transiting remains highly hazardous, and the U.S. Navy lacks the capacity to conduct counter\u2013mine operations quickly and expeditiously.\u00a0 During the Tanker Wars<\/a> in the late 1980s, U.S. Navy warships escorted civilian tankers through the Strait of Hormuz, with many Kuwaiti vessels reflagged as American vessels.\u00a0 The U.S. Navy has warships and other assets in the region that could assist with this mission, but the Navy is far smaller<\/a> than the 1980s Navy with the retirement<\/a> of the Oliver Hazard Perry-class frigates.\u00a0 Quantity has its own quality, and escorting civilian tankers would both expose the Navy warships to Iranian naval mines and projectiles while taking the warships away from other potentially critical missions.\u00a0 Unilateral, U.S.-only escort is not a viable option at this time. The United States should lay the groundwork to bring in other nations for a broader multinational escort initiative, an effort that President Trump has started<\/a> to undertake at least in the past 24 hours.\u00a0 But this, too, will be challenging. Japan, a longstanding U.S. ally, relies<\/a> on the Middle East for 95% of its oil. Japanese leaders\u00a0 have urged caution<\/a> following Trump\u2019s request to help secure shipping through the Strait of Hormuz, stating that such a deployment faces <\/a>an \u201cextremely high hurdle.\u201d\u00a0<\/p>\n What does naval doctrine say about mine countermeasures?<\/strong><\/p>\n Mine warfare under Navy doctrine<\/a> encompasses the countering of enemy-laid mines to permit friendly maneuver.\u00a0 Doctrine makes clear<\/a> that the most effective means for countering a mine threat is to prevent the laying of mines in the first place\u2014this is known as \u201coffensive mine countermeasures.\u201d Defensive<\/a> countermeasures are designed to counter mines once they have been laid. \u00a0 While it is hard to know with certainty whether Iran has mined the Strait of Hormuz, we may already be in the far, far more challenging defensive mine countermeasure phase.\u00a0<\/p>\n Navy doctrine requires<\/a> ships and aircraft engaging in mine countermeasures to have adequate force protection if conducted in a hostile environment\u2014a virtual impossibility at this time in light of the Shaheed<\/a> drone threat.\u00a0<\/p>\n Where do we go from here?<\/strong><\/p>\n Iran\u2019s attacks on civilian merchant vessels are clear violations of the law of armed conflict \u2014 the principle of distinction between civilian and military objects is among the most foundational rules of IHL, and there is no plausible military justification for striking Thai, Japanese, or Marshallese-flagged commercial ships. If reports of mining are confirmed, that escalation compounds the violation: Hague VIII<\/a> explicitly prohibits the use of mines to deny transit passage of international straits, and the obligation to protect neutral shipping from indiscriminate hazards is not suspended by armed conflict.<\/p>\n In any armed conflict, the enemy has a vote<\/a>, and Iran has apparently voted to close, or sharply suppress transit through, the Strait of Hormuz.\u00a0 Iran has correctly identified economic disruption as the pressure point<\/a> most likely to advantage it in the ongoing war.\u00a0 The Strait of Hormuz has long been recognized as one of the world\u2019s most strategically vital and legally complex maritime passages. The current conflict has made concrete what legal scholars and naval strategists have long warned: international law provides robust protections for transit passage rights, but it provides no reliable mechanism for enforcing them when a State actor is willing to violate them at scale.<\/p>\n Secretary Hegseth\u2019s dismissal of the Strait crisis limits the kind of active diplomatic and multilateral response that international law and operational realities demand. \u00a0 The United States faces a shrunken surface fleet and an untested and transitional<\/a> mine countermeasures capability.\u00a0 The Strait\u2019s geography inherently favors the defender. The Tanker War playbook of 1987-88 \u2014 convoy escort, reflagging, a large frigate fleet \u2014 is not readily available in 2026.\u00a0 If mining occurs, restoring safe transit will likely require a multinational naval effort and weeks of painstaking mine-countermeasure operations.\u00a0<\/p>\n * * *<\/p>\n The crisis in the Strait of Hormuz reveals a fundamental weakness in the law of the sea: transit passage is strongly protected in doctrine but difficult to enforce in practice when a coastal State is willing to violate the rules. In that sense, the Strait is not only a strategic chokepoint \u2014 it is a stress test for the international legal order governing global commerce.<\/p>\n