Transit passage is critical to maritime security. The recent grounding of the Ever Given in the Suez Canal demonstrates that, despite advances in commercial and military maritime technology, rudimentary free navigation of the world’s oceans remains paramount for international maritime security. While the causes of the six-day grounding of the 400-meter-long supertanker appear to be accidental, the Ever Given incident sheds light on how a similar event could occur in an international strait and impede the flow of global ship traffic. At the direction of a state or by a nonstate actor for economic, political, or strategic motivations, an incident such as the grounding of a supertanker could completely paralyze transit passage through narrow international straits and generate potentially grave consequences for international security and military operations across the globe.
Transit Passage and Law of the Sea
Freedom of navigation and the right of transit passage are codified in customary international law and the United Nations Convention on the Law of the Sea (UNCLOS). Ships and aircraft have the right of continuous and expeditious passage through international straits that connect an area of the high seas or an exclusive economic zone (EEZ) with another area of the high seas or EEZ (UNCLOS, art. 38). Coastal States may not impede transit passage through such straits during peacetime (art. 44) and ships and aircraft may transit through in normal modes of continuous and expeditious transit (art. 39), while respecting any relevant coastal State regulations regarding transit passage that are consistent with UNCLOS (art. 42).
International straits can be divided into five categories under international law (The Commander’s Handbook on the Law of Naval Operations, section 2.5.3.1), and are either governed by transit passage (UNCLOS, art. 37), nonsuspendable innocent passage (art. 17, art. 45(1)(b)), high seas freedom of navigation (art. 36), or specific treaty terms (art. 35(c)). The Strait of Hormuz is an international strait governed by the transit passage regime, as is the Strait of Malacca (art. 38). These narrow navigational “chokepoints” connect major areas of ocean that handle large amounts of global vessel traffic. As both international straits are overlapped by territorial seas of coastal states, the bordering states may designate sea lanes and traffic separation schemes with the aim of maintaining navigational security (art. 41). Such a scheme, however, must adhere to accepted international standards and be approved by the International Maritime Organization (IMO) (Commander’s Handbook, section 2.5.3.2).
Imagine if the Ever Given was transiting through one of these international straits and came to a grinding halt. Not only would the massive vessel block the flow of commercial traffic through the strait, she also likely would, depending on the timing and duration of the blockage, cause strategic security implications for military operations worldwide. Consequently, it is entirely probable to envision both state and nonstate actors intentionally employing a vessel as a strategic tool to block access through an international strait and prevent transit passage.
Strait Blockage as a Potent Tool for Adversaries
The grounding of the Ever Given illustrates a potentially effective tactic available to states and nonstate actors to thwart the flow of maritime traffic in international straits. A state could intentionally direct a vessel to run aground to delay and block transit passage for strategic, political, or economic purposes. A nonstate actor, in an act of maritime terrorism, hijacking, or piracy, could do the same. Whether with the volition of the ship’s master through order or compensation by the flag state or vessel’s owner, or a result of subterfuge through physical manipulation, damage, or cyber hacking into shipboard systems to cause navigational or other mishaps, there are a panoply of ways a vessel could become a strategic cork in a narrow strait.
State-directed or sponsored activity during peacetime to jam an international strait would be a clear violation of international law, and potentially constitute a “gray zone activity” under the threshold of armed conflict. Particularly, if the peacetime employment of a vessel to block a strait was intentionally timed and directed to impede the transit of a warship or other sovereign immune vessel, it potentially could result in a tense stand-off and escalation of force. Depending on the scenario, states and nonstate actors intentionally obstructing transit passage with a stalled or grounded vessel could be committing an act of maritime terrorism in violation of the Convention for the Suppression of Unlawful Acts against the Safety of Maritime Navigation, as well as a potentially violating the Convention on International Regulations for Preventing Collisions at Sea through obstruction of vessel traffic and risking collision at sea.
Operational Impacts of International Strait Blockage
Outside of the obvious impacts on commercial shipping and global commerce, a blockage of a key international strait poses significant operational and strategic implications for U.S. military operations and force deployment. U.S. warships regularly transit through the Strait of Hormuz to maintain forward presence in the Arabian Gulf, as well as the Strait of Malacca to conduct operations in the Pacific and Indian Oceans, and South China Sea. Even a brief blockage of the Strait of Hormuz could have deleterious domino effects on U.S. and coalition deployments to Europe, Africa, and the Middle East. Similarly, a blockage of the Strait of Malacca could negatively impact U.S. Pacific Fleet operations.
Blocked passage through an international strait could encumber scheduled carrier strike group deployments, stymie planned underway replenishments and refueling, delay strategic resupply of forward U.S. military bases, and wreak havoc on warship and force deployment timetables worldwide. U.S. warships and Military Sealift Command vessels may be stuck in a particular area of operations for longer than expected or face significant additional transit delays by rerouting. Thwarting movement could also place warships in situations of extremis-perhaps intentionally by the actors that caused the blockage-elevating the security posture of the warship, the fleet, and potentially resulting in confrontation at sea with the malign actor.
Conclusion
Delaying or blocking transit of warships and sovereign immune vessels through international straits would trigger a chain reaction of potentially harmful impacts to the military operations of the U.S. and its allies. While the Suez Canal itself is not an international strait as contemplated under international law, the Ever Given scenario raises the alarm of the possibility of a similar event occurring in an international strait. Whether an intentional blockage is a grey zone tactic by a state or an act of maritime terrorism by a non-state actor, the coastal states bordering the strait have an obligation under international law (UNCLOS, art. 43, 44) to clear the strait and ensure safety of navigation through it, regardless of who caused the obstruction. Transit passage remains a critical component of international maritime security, and the risks of such a blockage occurring again, perhaps intentionally, must be considered and adequately addressed in operational and strategic planning by the United States and its allies.
