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Law of Warfare

Unmanned Maritime Systems and Warships: Interpretations Under the Law of the Sea

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By Takeo Imura

Introduction

Unmanned systems technologies possess great potential for changing the landscape of military operations. Today’s unmanned systems include aircraft, ground vehicles, and surface and subsurface vessels.

Military forces are experimenting with unmanned systems, which are expected to help the military reduce casualties and increase mission endurance. The U.S. Navy enumerates various missions expected for unmanned systems and plans to substitute them for some existing manned platforms.1

Treating unmanned vessels as warships requires examining whether they meet the definition of a warship under the United Nations Convention on the Law of the Sea (UNCLOS). The legal status of naval vessels under UNCLOS varies widely depending on whether a navy operates its ships as warships, non-commercial government vessels, or accessories to conventional warships.        

This paper discusses whether unmanned systems can be considered warships under UNCLOS, especially with today’s voracious appetite for developing the technology; however, the legal status of unmanned vessels as warships remains uncertain. International agreements on the legal status of unmanned vessels would help establish the legitimacy of naval operations employing them.

Unmanned Vessels and Warship Status

Article 29 defines a warship as:

“A ship belonging to the armed forces of a State bearing the external marks distinguishing such ships of its nationality, under the command of an officer duly commissioned by the government of the State and whose name appears in the appropriate service list or its equivalent, and manned by a crew which is under regular armed forces discipline.”2

Accordingly, four conditions must be met to determine whether unmanned vessels can be considered warships under UNCLOS. They are defined as a “ship,” bear “external marks” of the possessing flag state, are “under the command of an officer,” and are “manned by crew.” Each of these conditions is considered in the following analysis.

Ships

UNCLOS does not provide a specific definition of what constitutes a ship. Article 91 states, “[s]hips have the nationality of the State whose flag they are entitled to fly.”3 Further, article 92 provides “[s]hips shall sail under the flag of one State only…[and a] ship may not change its flag during a voyage or while in a port of call, save in the case of a real transfer of ownership or change of registry.”4 Accordingly, UNCLOS declares that all ships must maintain a genuine link with their state and fly their flag to show who possesses jurisdiction.5 Article 94 mandates that “[e]very State shall effectively exercise its jurisdiction and control in administrative, technical and social matters over ships flying its flag.”6 There are certain requirements the flag state must meet to maintain a genuine link between the ship and the State, such as undertaking measures “to ensure safety at sea.”7 Paragraph 3b of the same article requires flag states to regulate “the manning of ships, labour conditions and the training of crews, taking into account the applicable international instruments.”8

In the case of unmanned vessels, it would be difficult for a flag state to fulfill these requirements since they are unmanned. However, if the word “manning” is considered part of a greater flag state duty to ensure safety at sea, then this requirement can readily be met. Manning should not simply mean individuals being physically aboard. Additionally, the Vienna Convention on the Law of Treaties, Article 31, states, “any subsequent practice in the application of the treaty which establishes the agreement of the parties regarding its interpretation” is included in the meaning.9 Accordingly, the states party to UNCLOS may recognize unmanned vessels as ships unless such interpretation is contrary to the treaty’s terms, its object, or purpose and is evidenced by the subsequent practices of the parties. Evidence that many states are moving to accept unmanned vessels as ships can be found in the maritime transportation domain. Specifically, the International Maritime Organization (IMO) developed the maritime autonomous surface ship concept, or MASS.10 Considering the latitudes provided by the provisions of the Vienna Convention on the Law of Treaties, the IMO’s development of MASS demonstrates the definition of “manning” is not an obstacle to accepting unmanned vessels as ships under UNCLOS if flag states fill their requirements.11

UNCLOS is not the only treaty that defines what constitutes a ship. For instance, the International Convention for the Prevention of Pollution from Ships (MARPOL) defines a ship as “a vessel of any type whatsoever operating in the marine environment.”12 Also, the Convention on the International Regulations for Preventing Collisions at Sea (COLREGs), Part A, Rule 3a states, “[t]he word vessel includes every description of watercraft… being used as a means of transportation on water.”13 Similar to MARPOL, this definition encompasses a wide variety of vehicles, with the main difference being whether the vehicle is used for transportation on water. However, a ship without transporting something is difficult to imagine. Even unmanned vessels carry payloads that are not essential for navigation. For example, the SD1045 unmanned vessel is used for maritime environment research and can change payloads to adjust to user demands.14

Finally, the 1972 Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Convention) defines a ship more broadly as a “waterborne…craft of any type whatsoever….”15 Based on this provision, a vessel can be interpreted as any vehicle that operates in or above water.

In conclusion, unmanned vessels can be recognized as ships under UNCLOS or other treaties, given the broad definition of a “ship.” Therefore, a flag state has the legal authority to decide what device it will regard as a ship, provided it meets the minimal requirements of UNCLOS.16

External Marks

Generally, a flag, referred to as a naval ensign, is used as an external mark to show the status and nationality of a warship. Setting up a naval ensign on unmanned surface vessels may be possible. In the case of unmanned underwater vessels (UUVs), this requirement probably would need to be fulfilled by painting a flag or other substitute markings.

Under the Command of an Officer

There is no unified definition of the word “command.” One paper discussed the subject and stated, “…being in command does not require the person to make every decision and guide every action, and that the commander can be removed from the action to some extent.”17 This view is based on the military doctrines of the United States, Netherlands, France, and the North Atlantic Treaty Organization. This approach can be applied to the command of unmanned vessels, but the outcome may depend on the vessel’s degree of autonomy. There are three levels of human participation in the command of unmanned systems: “in the loop,” “on the loop,” and “out of the loop.”18

The concept of “in the loop” is that a human is continuously and significantly involved in the actions of the unmanned vessels, operating it remotely.19 The concept of “human on the loop” is one in which humans monitor unmanned vessels and influence autonomous decisions without directly operating the system.20 The human has veto power over the actions of the unmanned vessels, which otherwise operate independently.21 “Human out of the loop” applies when humans are not involved in autonomous decisions – the system has full operational autonomy. Human control relates to the software programming that governs the unmanned vessel’s actions in such cases.22

Unmanned vessels with “humans out of the loop” are controlled by high-end autonomous algorithms. Such unmanned systems equipped with weapons are categorized as lethal autonomous weapons systems (LAWS). Rules governing the operation of LAWS are currently one of the most controversial subjects in international law. Advocates for using LAWS in military operations focus on their contribution to military advantage as a moral justification.23 LAWS can reduce the loss of human life and expand operations into previously inaccessible areas.24 Further, they argue LAWS meet the requirements of morality because “autonomous robots in the future will be able to act more “humanely” on the battlefield […because] they do not need to be programmed with a self-preservation instinct.”25 Those who oppose the use of LAWS focus on the problem of accountability.26 Given the system’s autonomy and the unpredictability of decisions made by machine learning, it would be hard to identify the cause of flawed decisions and assign accountability. As one article puts it, “Where a human being makes the decision to use force against a target, there is a clear chain of accountability, stretching from whoever actually ‘pulled the trigger’ to the commander who gave the order.” 27 This is not the case with LAWS. While the commander can be identified and held accountable for the operation of unmanned systems with “in the loop” or “on the loop,” this is not the case with “out of the loop” systems.

Some propose that “[s]ince a commander can be held accountable for an autonomous human subordinate, holding a commander accountable for an autonomous robot subordinate may appear analogous.”28 If so, commanders that employ unmanned systems cannot escape the responsibility for their operation, whether a human is in the loop or not. Traditionally, command responsibility is only implicated based on reasonable foreseeability of an untoward action, and the commander failed to prevent it.29 The possibility that a commander can reasonably foresee what LAWS will do is remote. Even if unmanned systems were only operated for non-combat missions, such as information gathering in peacetime, responsibility for non-lethal violations of UNCLOS or domestic law would remain an issue. Usually, in the case of manned warships, the responsibility falls on the tactical-level commander, such as the commanding officer.

One solution some have proposed is to incorporate a recording function to provide a detailed operational log against which to hold a commander responsible. But is the tactical commander best positioned to reasonably foresee what the LAWS will do? Whether command responsibility lies with the tactical commander who deployed the system, the operational level commander who allocated the system to the tactical commander, or the commander responsible for the design and introduction of the system into the fleet remains unclear and the subject of debate. However, for the “command” requirement of UNCLOS Article 29 to be fulfilled, a commander must be aware of the operations conducted under his or her command. Since it is possible this will not be the case with LAWS, with humans “out of the loop,” it is an issue that remains unaddressed by international law.

Manned by a Crew

“Manned” is generally understood as a crew aboard a vessel. However, other laws that regulate or define ships do not include the condition of a crew being aboard. For example, U.S. code Title 33, section 4101 states unmanned systems are “…designed to function without an on-board human presence…”30 Other scholars point out in regard to the safety of life at sea (SOLAS),

“SOLAS relies on states to ensure the safe manning of their ships. There is no minimum number of persons required to be on board so long as the primary safety concern is met. It can, therefore, be argued that a crew numbering zero is technically ‘adequate’ provided the operation is safe.”31

At least in the private sector, crews are not required to be physically aboard unmanned vessels. Also, a boarded crew is not required in COLREG or MARPOL. That said, the history of the definition of warships might be different from ordinary ships.

A warship has a specific definition derived from the history of privateers in the 16th to mid-19th centuries.32 A privateer “…was a privately-owned vessel, outfitted as a warship, authorized by a recognized national government, through the issuance of a commission to attack.”33 On the one hand, privateers did not always come under the control of the government, and abuse of its rights and abnormal practices occurred. Ultimately, privateering was abolished in 1856 by the Paris Declaration.34 Nevertheless, the use of civilian ships in wartime continued. The Hague Convention No. VII, on International Convention relative to the Conversion of Merchant-ships in Warships of 18 October 1907, provided regulations about converting merchants to warships. A merchant ship converted to a warship was given the rights of a warship (mainly belligerent rights).35 The Hague Convention influenced the drafting of UNCLOS, specifically the requirements in Article 29.36 The key to properly reading UNCLOS Article 29 is to focus on the requirement that “crews [be] under the appropriate discipline.” Physical manning is not the primary point of the article.37 Thus, while some form of human control of the warship is needed to fulfill the condition of the existence of a crew, physical manning is not required.

Conclusion

This analysis discussed whether navies should operate unmanned vessels as warships under the provision of UNCLOS Article 29. Considering the discussions above, one can say that unmanned vessels with “human in the loop” or “human on the loop” fulfill the conditions of Article 29. However, unmanned vessels with “humans out of the loop” do not fulfill the current conditions of Article 29 and do not acquire the status of warships.

Undoubtedly, details of how to fill the requirements of “under the command of an officer” and “manned by crew” will be controversial with “out of the loop” unmanned systems. Concerning the command requirement, this paper concludes that commanders are at least responsible for the decisions to deploy unmanned systems, but the level of command responsibility remains unclear. Concerning the requirement that a ship has a crew, while some form of involvement of a ‘crew’ in the operation of the unmanned systems can fill the condition of Article 29, it might be difficult to meet the condition if autonomy develops to such a level that no crew involvement is required once the system is deployed; to be accorded the status of a warship requires “a crew which is under regular armed forces discipline.” Accordingly, navies that want to operate unmanned systems should carefully evaluate their desired missions and how to manage the command and crew requirements, especially in cases where unmanned systems will be fully autonomous.

Takeo Imura is an operational legal advisor for the Japan Maritime Self-Defense Force. He previously served as a faculty member in the Japan Maritime Self-Defense Force Command and Staff College Operational Legal Office and as a military professor at the U.S. Naval War College Stockton Center for International Law. Before transitioning into law, was a submarine officer for nine years.

References

1. DEPARTMENT OF THE NAVY, OFFICE OF THE CHIEF OF NAVAL OPERATIONS, HEADQUARTERS U.S. MARINE CORPS, DEPARTMENT OF HOMELAND SECURITY AND U.S. COAST GUARD, THE COMMANDER’S HANDBOOK ON THE LAW OF NAVAL OPERATIONS, NAVY WARFARE DEVELOPMENT COMMAND (Mar 2022), pg., 2.3.4.

2. United Nations Convention on the Law of the Sea, art 29, Dec. 10, 1982, 1833 U.N.T.S. 413, pg., 408.

3. Ibid. pg., 433.

4. Ibid.

5. No article in UNCLOS stipulates that a ship without nationality is itself illegal. However, the fact that stateless vessels are listed among the vessels subject to on-site inspection under article 110, along with pirate ships and unauthorized broadcasting ships, suggests that non-nationality ships are not positive entities. Besides, in chapter 5 of Maritime Law Enforcement, page 56 of “Maritime Crime: A Manual for Criminal Justice Practitioners” by the United Nations Office on Crime and Drugs in 2017 said ” States were traditionally opposed to the idea that a ship might have no nationality because this would imply that there is no jurisdiction applicable to that vessel. This would be against the desire of States to ensure that proscribed conduct is subject to some level of jurisdiction in all places…” Thus, a ship without nationality would understood as an unacceptable existence.

6. United Nations Convention on the Law of the Sea, Supra note 2, pg., 434.

7. Ibid.

8. Ibid.

9. Vienna Convention on The Law of Treaties, art 31, May 23, 1969, 1155 U.N.T.S. 332. pg., 340.

10. Autonomous shipping, International Maritime Organization, https://www.imo.org/en/MediaCentre/HotTopics/Pages/Autonomous-shipping.aspx (last visited Jun 27, 2024).

11. These requirements are found in UNCLOS Articles 91, 92, and 94.

12. International Convention for the prevention of pollution from ships, 1973, art 2(4), Feb. 17, 1978, 1340 U.N.T.S. 184, pg., 185.

13. Convention on the international regulations for preventing collisions at sea, 1972, Part A Rule 3, Oct. 20, 1972, 1050 U.N.T.S. 18, pg., 22.

14. THE WORLD’S MOST CAPABLE USVS, SAILDRONE, https://www.saildrone.com/technology/vehicles (last visited Jun 10, 2024).

15. Convention on the prevention of marine pollution by dumping of wastes and other matter, art 3(2) Dec. 29, 1972, 1046 U.N.T.S. 138, pg., 140.

16. Natalie Klein, How should the law treat underwater maritime autonomous vehicles?, The Strategist (May 4, 2023), https://www.aspistrategist.org.au/how-should-the-law-treat-underwater-maritime-autonomous-vehicles, (last visited Jun 11, 2024). (Discusses the legal challenges for the Australian Defence Force to adopt Maritime Autonomous Vehicles).

17. Rain Liivoja, Eve Massingham, and Simon McKenzie, The Legal Requirement for Command and the Future of Autonomous Military Platforms, 99 Int’l L. Stud. 638, 652 (2022) (discussing the definition of the word “command”).

18. Paul Scharre, Michael C. Horowitz, Working Paper: An Introduction To Autonomy In Weapon Systems, Center For a New American Security (Feb 13, 2015), https://www.cnas.org/publications/reports/an-introduction-to-autonomy-in-weapon-systems (last visited Jun 10, 2024), pg., 6.

19. Christof Heyns (Special Rapporteur), Report of the Special Rapporteur on extrajudicial,

summary or arbitrary executions, U.N. doc A/HRC/23/47 (2013), 39, 41, at 8.

20. Ibid.

21. Christof Heyns, Supra note 19, pg., 8.

22. Ibid.

23. Amitai Etzioni, Oren Etzioni, Pros and Cons of Autonomous Weapons Systems, Military Review 72, 72 (May-June 2017), https://www.armyupress.army.mil/Journals/Military-Review/English-Edition-Archives/May-June-2017/Pros-and-Cons-of-Autonomous-Weapons-Systems/,(introducing opinions about discussion of Autonomous Weapons Systems).

24. Ibid.

25. Ibid. pg., 74.

26. Ibid. pg., 75.

27. Amitai Etzioni, Oren Etzioni, Supra note 23. Pg., 75.

28. Christof Heyns, Supra note 19, pg., 15.

29. Ibid.

30. 33 U.S. Code § 4101 (2024).

31. Robert Veal, Michael Tsimplis and Andrew Serdy, The legal status and operation of unmanned maritime vehicles, Ocean Development & International Law (2019), https://doi.org/10.1080/00908320.2018.1502500 (last visited Jun 10, 2024), pg. 36.

32. Rain Liivoja, Eve Massingham, and Simon McKenzie, Supra note 17, pg. 660.

33. David J Bederman, Max Planck Encyclopedias of International Law(Subject: “Privateering”), Oxford Public International Law (Oct 2008), https://opil.ouplaw.com/display/10.1093/law:epil/9780199231690/law-9780199231690-e382?rskey=pMAj9J&result=1&prd=MPIL (last visited Jun 10, 2024).

34. Ibid.

35. Rain Liivoja, Eve Massingham, and Simon McKenzie, Supra note 17, pg., 662.

36. Myron H. Nordquist, Neal R. Grandy, Satya N. Nandan, and Shabtai Rosenne, United Nations Convention on the Law of the Sea 1982, Volume II A Commentary, 249, Martinus Nijioff Publishers(Aug 1993). Note that these were already included in the draft of articles made by the International Law Committee in 1956.

37. Malgorzata Materna, Adjusting the Aperture: The International Law Case for Qualifying Unmanned Vessels as Warships, 100 Int’l L. Stud. 472, 452 (2023) (discussing differences in crew condition of warships between HC7 and UNCLOS).

Featured Image: A Seahawk medium displacement unmanned surface vessel participates in U.S. Pacific Fleet’s Unmanned Systems Integrated Battle Problem in the Pacific Ocean, April 21, 2021 (Photo by Chief Mass Communication Specialist Shannon Renfroe/U.S. Navy)

Law of Warfare

Rules of Engagement and Undersea Incursions: Reacting to Foreign Submarines in Territorial Waters

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This article is part of a series that will explore the use and legal issues surrounding military zones employed during peace and war to control the entry, exit, and activities of forces operating in these zones. These works build on the previous Maritime Operational Zones Manual published by the Stockton Center for International Law predecessor’s, the International Law Department, of the U.S. Naval War College. A new Maritime Operational Zones Manual is forthcoming.

By LtCol Brent Stricker

“We have attacked, fired upon, and dropped depth charges on a submarine operating in defensive sea area.”–USS Ward (DD-139) December 7, 1941, Pearl Harbor, Hawaii.

Submerged foreign submarines in a nation’s territorial sea pose a unique situation that is inconsistent with the rule of innocent passage. Under certain circumstances, their concealed presence without the consent of the coastal state could be considered a threat to the territorial integrity or political independence of the coastal state. A modern submarine fulfills its peacetime mission and combat role while submerged. If the coastal state detects a submerged submarine in the territorial sea, it is faced with a dilemma on the appropriate measures that can be used to force the submarine to surface or leave the territorial sea. The recent sabotage of the Nord Stream pipeline and the vulnerability of the world’s vast subsea network of electricity and network cables highlights the danger posed by unknown submersibles.

Norway and Sweden have faced this problem for more than 50 years from suspected Soviet and later Russian submarines. Both countries have used warning shots in an attempt to signal the submerged contacts to surface or leave the area. Use of explosives in this manner, however, could be misinterpreted as an attack on the submarine. Balancing the protection of territorial sovereignty with avoiding escalation poses a predicament.

Innocent Passage

All ships, including warships, enjoy the right of innocent passage through the territorial seas of a coastal state without prior notification or consent. This rule was discussed in detail in the Corfu Channel case before becoming codified in the United Nations Convention on the Law of the Sea. The Corfu Channel is a narrow passage between Albania and the Greek island of Corfu. The United Kingdom’s Royal Navy was confronted by Albanian coastal artillery fire when transiting the channel in May 1946. In October 1946, two Royal Navy destroyers transited the channel while at action stations to be prepared to respond to coastal artillery fire or other threat posed by the Albanians. These destroyers struck naval mines laid in the channel. As a result, in November 1946, the Royal Navy conducted minesweeping operations to clear the channel.

The United Kingdom brought a case against Albania in the International Court of Justice seeking reparations for the loss of life and damages to its warships. The ICJ upheld the Royal Navy’s right of innocent passage through Albanian territorial waters, rejecting Albania’s arguments that the ships were not in innocent passage because they were sailing in formation and the sailors on board were at action stations. Rather, the Court found that sailing in formation and running at action stations were appropriate defensive measures. The Court found that the minesweeping operation was inconsistent with innocent passage and a violation of Albanian sovereignty, rejecting the British arguments that this was a measure of “self-protection.” Corfu Channel illustrates how innocent passage may include defensive measures. The case has long presented a conundrum because it determined that states are entitled to innocent passage, yet are restrained from taking defensive action, such as minesweeping, to exercise their right.  

Innocent passage is governed by the United Nations Convention on the Law of the Sea (UNCLOS). Norway and Sweden are signatories to UNCLOS, and the United States, while not a signatory, recognizes much of it as customary international law. UNCLOS codified the right of innocent passage in Articles 17-21. Innocent passage must “not be prejudicial to the peace, good order, or security of the coastal state.” A foreign vessel’s passage is not innocent if its actions constitute “any threat or use of force against the sovereignty, territorial integrity or political independence of the coastal State.” A special provision for submarines, Article 20, requires submarines engaged in innocent passage to “navigate on the surface and to show their flag.”

A coastal state that discovers an unknown submerged contact in its territorial sea is faced with a dilemma. Examples from Norway and Sweden of submerged contacts lingering in their territorial waters are inconsistent with the definitions of both passage and innocent passage. The coastal state, under Article 25 of UNCLOS, may “take the necessary steps in its territorial sea to prevent passage which is not innocent.” There is no agreement on exactly what steps are deemed necessary. Furthermore, these measures are limited when applied to sovereign immune warships. Thus, while an unknown submerged contact is not exercising innocent passage, it is unclear what measures a coastal state can apply to exercise its rights under Article 25. Articles 30 and 31 of UNCLOS allow a coastal state to require the submerged contact to leave its territorial sea and places liability for any damages on the flag state of the submerged contact. Armed force against an unknown submerged contact, however, may only be used in self-defense under Article 51 of the UN Charter. In most cases, use of force would not be justified simply because the submarine is submerged or refuses to surface and the mere presence of the submarine does is not tantamount to an “armed attack.” This determination is complicated when the submerged contact’s intensions cannot be ascertained.

Norway

Norway has been dealing with suspected intrusions by foreign submarines for more than 50 years. These contacts in Norwegian fjords are difficult to track due to the mixing of fresh water runoff and salt water in the fjords which can provide cover for submarines from sonar detection. Acoustic detection is complicated by the fjord’s subsurface structure, currents, and civilian surface traffic. For two weeks in November 1972, Norwegian vessels aided by Norwegian and British aircraft attempted to locate and force to the surface an unknown underwater contact, believed to be of Soviet or Warsaw Pact origin, in the Sogne Fjord using depth charges. Hand grenades and then depth charges were used to signal to the underwater contact to surface. Ultimately, the Ministry of Defense was given permission to sink the contact if it did not surface and identify itself.

For the Norwegians to use force against the unknown submerged contact, they would need to articulate how an otherwise benign submerged vessel posed an imminent threat that would justify the use of force in self-defense. Violating Article 21 of UNCLOS in and of itself does not constitute such a threat of imminent attack, even if the submarine is engaged in an intelligence or reconnaissance mission. Such a mission may be illegal under Norway’s domestic law, but it does not imply an illegal use of force, let alone an armed attack.

In limited situations, the location and duration of the unknown submarine in territorial waters could be considered as a threat, as noted in the radio transmission of the USS Ward when it engaged an unknown submarine in a defensive sea area. The Norwegians would be more concerned by the location of the unknown submersible if it were in such an area or in close proximity to another sensitive military exercise or base. The longer the submarine remained at depth, the greater potential one might consider it laying in wait to attack. Nonetheless, the Norwegians employed an escalating use of force in 1972 with attempts to signal with hand grenades and ultimately culminating with firing anti-submarine missiles at the suspected target. The Norwegians were ultimately unable to force the contact to the surface, identify it, or sink it.

Norwegian experiences with unknown submarine contacts continued over the decades. The official Norwegian policy on the use of force remained somewhat ambiguous. In 1983, Brigadier Asbjorn V. Lerheim stated on the use of force, “It is a tough decision, it is still peacetime, and you can’t really destroy a submarine . . . it is not an attack on Norwegian soil.” Norway seems to have adopted a set of measures to escalate the use of force against these intrusions. The first measure is to signal the submarine to surface. If the submarine complies, it would be taken under escort. If not, depth charges would be dropped within 300 meters from the submarine with a two-minute interval to indicate this was a signaling measure, not an attack. If this failed to surface the submarine, Norwegian captains were authorized to attack with depth charges, but torpedoes were prohibited in the attack because of the potential of catastrophic damage to the boat and loss of the entire crew. It is speculated that the anti-submarine missiles fired in 1972 used homing devices and proximity fuses and were not a real attempt to hit the submarine.

Suspected Soviet incursions into Norwegian territorial waters continued as late as 1990. Norwegian authorities received reports of suspected submarines in the summer of 1990 at Skipton, a Norwegian bay twenty-five miles from the Russian border. The area was put under surveillance when, in November 1990, a mini-submarine was observed briefly on the surface. The sea floor was examined and a series of tracks were found that indicated a submersible crawler had been deployed. Similar tracks were discovered elsewhere in Sweden and Norway near military installations. The Soviet Northern Fleet possessed such miniature submarines at the time. It was speculated that the miniature submarine was launched from a nearby mother ship to conduct a Spetsnaz training or reconnaissance mission.

As late as 2021, Norway was subjected to an undersea intrusion by unknown submersibles. The Norwegian Institute of Marine Research operates a network of undersea sensors in northern Norway to monitor the marine environment. It can also be used to monitor submarines in the area. These sensors are interconnected by a series of fiber optic cables. In April 2021, it was discovered that 2.5 miles of fiber optic cable had been cut and stolen. Several of the sensors had been tampered with and moved. The reason for the intrusion is speculative but includes the potential for reverse engineering.

Sweden

Like Norway, Sweden has been troubled by intrusions of foreign submarines in its territorial waters for a similar period of time. Unlike Norway, Sweden has actually caught one submarine on the surface in the infamous “Whiskey on the Rocks” incident in 1981. This incident noted increased intrusions throughout the 1980s that have continued as late as the 2010s. To date, the Whiskey is the only foreign submarine caught on the surface in Swedish territorial waters.

On October 27, 1981, a Soviet Whiskey class submarine, the U-137, was found grounded on a rock in Swedish territorial waters. The Whiskey was an early Cold War diesel electric submarine, not a nuclear-powered submarine. The Swedish Navy contacted the submarine’s captain, Captain Second Rank A. M. Gushchin, who claimed a navigational error. Captain Gushchin claimed he thought he was 20 miles off the Polish coast when the collision occurred. This claim is rather dubious considering the submarine had transited submerged through a “perilous series of narrow straits infested with rocks and islands” before the grounding. The submarine’s grounding within ten kilometers of the Swedish naval base at Karlskrona while a major naval exercise was being conducted was certainly not just a coincidence brought about by a navigational error. Upon inspection, Swedish officials found no problems with the boat’s navigational equipment and noted its logbook had been altered.

The boat remained grounded for eleven days while the Swedish authorities inspected the submarine and questioned the captain. The Soviet Union responded by sending a flotilla of warships that stayed just outside Swedish waters. The Swedish Prime Minister made a shocking announcement on November 5, 1981, that the submarine was suspected of carrying nuclear weapons. The Swedish government made demands to the Soviets before releasing the submarine. However, weather intervened and Sweden released the submarine before these demands were met. The submarine was exposed to gale force winds and was listing 17 degrees. Swedish authorities were concerned that the boat’s battery acid could spill and cause a fire or release chlorine gas that could kill the crew. Swedish authorities stopped the captain’s interrogation and boat inspection, refloated the boat, and the submarine left on November 6, 1981.

Following this incident, the Swedish government released the Submarine Defense Commission Report in 1983, which detailed the history of foreign submarines intruding into Swedish waters. Prior to the Whiskey incident, and even subsequently, critics had claimed these submarine scares were an excuse to increase the Navy’s budget. The report detailed how foreign submarines entered Swedish waters typically one to two times a year in the 1970s before a dramatic increase during the 1980s. These incursions were concentrated around naval facilities such as coastal defense points, ports, sensor networks, and minefields.

The Report and increased submarine intrusions led to a change in Swedish Rules of Engagement (ROE) applicable to submarine contacts. Prior rules prohibited a commander from firing on an unknown contact without authorization from the civilian leadership. The Swedish Navy was only allowed to make contact with the submarine to identify it and escort it out of Swedish waters. The new ROE allowed the submarine to be fired upon without warning. Initially, warning shots were to be used, either through the employment of depth charges or missiles. The ROE were intended to prevent the damage or destruction of the submarine, but the ROE made a distinction on the location and behavior of the contact. If the submarine was located in Sweden’s outer waters, these are waters beyond the internal archipelago to the 12-mile limit, it would be warned and escorted out. If the submarine was found in internal waters, these are waters of Sweden’s internal archipelago, and refused to leave or proceeded further, it could be treated as hostile and force designed to damage or destroy the submarine could be used.

The Swedish ROE may have contributed to their inability to force submarines to the surface. If they employed depth charges or other devices with an eye toward avoiding damaging the detected submarines, the submarines could simply ignore these attempts. There is evidence that the Swedish ASW may have damaged a submarine. In the summer of 1988, eight pieces of unknown foreign submarine rescue equipment were recovered in the Stockholm archipelago. Similar equipment had been recovered in the 1970s and 80s.

The Swedish Navy continued to deal with foreign submarines intruding into Swedish waters throughout the 1980s. The government stopped providing statistics on these incursions in 1987. Subsequent reports have been vague in their descriptions. This may be to avoid highlighting their inability to stop or deter these incursions.

There is evidence that these incursions did occur. The Swedish Navy noted that these incursions have become more sophisticated with the use of multiple submarines, miniature submarines, and divers. The evidence for these incursions comes from sightings, sonar, and magnetic detection from Swedish sensor networks. There has also been evidence of keel marks and track marks on the sea floor similar to the Norwegian miniature submarine event noted above.

The miniature submarines may have also allowed military forces to surreptitiously land on Swedish territory. Between 3 to 6 March 1984, Swedish forces fired at swimmers on the island of Almo. The island was searched and food caches were located. The Swedes have also noted attacks on their “submarine nets, break-ins ashore, to the disruption and destruction of underwater mine lines.” In one case, they were blamed for the theft of a naval mine. Most shockingly, in 1985 fisherman pulled a drowned swimmer up in their nets. The nets had been placed illegally near a naval mine. It is presumed the diver was scouting the mine when he became entangled and drowned. The fisherman did not recover the body and abandoned their nets. When Swedish authorities investigated, the body had been cut out of the net and removed by unknown persons.

Conclusion

This historic submarine incursions remain relevant today, particularly considering heightened tensions from the Russian invasion of Ukraine and the recent application of Finland and Sweden to join the North Atlantic Treaty Organization. Much like the Norwegian fjords, the Swedish archipelago would be an area for these submarines to operate. The reasons for the incursions remain relevant today for any NATO-Russian conflict whether it be to conduct reconnaissance or the insertion of Special Forces. If there is a repeat of one of these Cold War examples such as a stranded submarine like the Whiskey, or more concerning, NATO forces hunting a submarine contact, the consequences could be manifold. First, NATO forces chasing a submarine contact trying to force it to surface might be viewed as an attack on the submarine. The use of explosives to signal a submarine might accidentally damage it or injure the crew. These signals could be misinterpreted as an attack allowing or even requiring a submarine to respond in self-defense. Second, any hostilities in territorial waters directly implicates the collective self-defense clause of Article 5 of the North Atlantic Treaty.

The conduct of Russian submarine espionage in the territorial seas of its neighbors presents one of the greatest challenges to avoiding conflict in the Baltic Sea. These incidents reveal the gap between the law of the sea and the use of force in self-defense against an armed attack. The Nordic coastal states must walk a fine line between protecting their territorial integrity and avoiding escalation of an incident that might quickly spin out of control.

LtCol Brent Stricker, U.S. Marine Corps, serves as the Director for Expeditionary Operations and as a military professor of international law at the Stockton Center for International Law, U.S. Naval War College. The views presented are those of the author and do not necessarily reflect the policy or position of the U.S. Marine Corps, the U.S. Navy, the Naval War College, or the Department of Defense.

Featured Image: Russian Kilo-class submarine in the English Channel. (UK Ministry of Defence photo via Wikimedia Commons)

Law of Warfare

East China Sea Air Defense Identification Zones: A Primer

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This article is part of a series that will explore the use and legal issues surrounding military zones employed during peace and war to control the entry, exit, and activities of forces operating in these zones. These works build on the previous Maritime Operational Zones Manual published by the Stockton Center for International Law predecessor’s, the International Law Department, of the U.S. Naval War College. A new Maritime Operational Zones Manual is forthcoming.

By LtCol Brent Stricker

Tensions could be high in East Asia when a civil aircraft flying in international airspace over the East China Sea (ECS) finds itself intercepted by military fighter aircraft. These aircraft are part of an Air Defense Identification Zone (ADIZ) system which exists to identify and control aircraft approaching a nation’s airspace. Intercepted aircraft can be ordered to land in a country they never intended to visit, shot down for failure to comply, or perhaps suffer a mid-air collision as occurred in the EP-3 incident. Unfortunately in the ECS, there are four overlapping ADIZs (Japan, Korea, China, and Taiwan) increasing the risk for civil aircraft navigating the area.

The patchwork of overlapping Air Defense Identification Zones (ADIZs) covering much of the East China Sea represents a potential flashpoint for conflict. A brief survey of the history, purpose, and location of these zones can help frame these risks for the future.

A Short History of the ADIZ

International law governing aircraft evolved after the First World War with the adoption of the 1919 Paris Convention for the Regulation of Aerial Navigation.1 The Paris Convention treated international air space like the high seas, adopting the principle of caelum liberum (freedom of the skies) where national sovereignty could not be asserted.2 The Paris Convention was replaced by the 1944 Convention on International Civil Aviation (Chicago Convention). The Chicago Convention maintains the distinction between national and international airspace but only applies to civil aircraft.3 State aircraft, which include military, customs, and police aircraft, are exempt from compliance with the convention but must operate with “due regard” for the safety of civil aircraft and may not fly over the territory, including the territorial sea, of or land in another state without permission.4

An Air Defense Identification Zone (ADIZ) is defined in Annex 15 of the Chicago Convention as a “Special designated airspace of defined dimensions within which aircraft are required to comply with special identification and/or reporting procedures additional to those related to the provision of air traffic services (ATS).”5 Information regarding the establishment of ADIZs and their reporting requirements is available in each states’ Aviation Information Publication.6

The United States pioneered this concept by creating the first ADIZ in 1950 and encouraging its allies, such as Norway, Iceland, Japan, Taiwan, and South Korea, to establish similar zones. An ADIZ can extend beyond national air space into international airspace to allow states to identify aircraft approaching their territory to ensure they are not a hostile threat. ADIZ reporting requirements vary by state, but all have requirements to identify approaching aircraft and their origin and destination. An ADIZ is analogous to port entry requirements or conditions a state imposes on ships entering or transiting its internal waters.7 Since the end of the Cold War, ADIZs have declined in use. Norway and Iceland’s ADIZs, for example, were decommissioned after the Cold War ended.8

While states exercise sovereignty over their national airspace, an ADIZ that extends beyond a state’s territorial sea only allows the state to establish “conditions and procedures for entry into its national airspace.”9 These conditions and procedures may include filing a flight plan before departure, aircraft identification requirements, and positional updates.10 Aircraft entering an ADIZ that do not intend to enter national airspace continue to enjoy high seas freedoms of overflight and are not required to comply with ADIZ requirements.11

A civil aircraft entering an ADIZ that fails to comply with the conditions and procedures for entry into national airspace may be considered a potential threat. Typically, such non-compliant aircraft are intercepted by military aircraft to determine their intentions. Violation of ADIZ requirements does not, however, authorize a military aircraft to attack a civil aircraft unless it commits a hostile act or demonstrates hostile intent.12 For example, in February 1961, a Soviet state aircraft was flying in international airspace over the Mediterranean Sea 80 miles off the coast of French Algeria when it was intercepted by a French fighter.13 The French claimed that the aircraft had entered a declared “zone of identification,” had diverted from its declared flight path, and was approaching Algeria without responding to radio challenges.14 Although only warning shots were fired, the diplomatic fallout of the incident was a recognition by both the Eastern and Western powers that there was a free right to navigation in international airspace even within an ADIZ.15

East China Sea ADIZ

ADIZs have been established in North Asia by the People’s Republic of China (PRC), Taiwan, South Korea, and Japan. The PRC ADIZ differs from the others in that it intentionally overlaps portions of the other three. The PRC ADIZ also includes the airspace above Japanese administered territory16 and appears to assert jurisdiction over international air space.17  (The People’s Republic of China AIP can be accessed here.)18

The PRC declared an ADIZ in the East China Sea on November 23, 2013.19 This ADIZ differs from other zones because claims to apply to all aircraft transiting the zone whether or not they intend to enter PRC national airspace. Such a requirement is inconsistent with international law.20 The zone requires all aircraft transiting through the zone “to follow identification rules, including filing a flight plan with the PRC’s Ministry of Foreign Affairs or Civil Aviation Administration; maintaining two-way radio communications and responding promptly to identification requests from the Ministry of National Defense; operating a secondary radar responder (if equipped); and marking nationalities and logos clearly.”21 The zone therefore illegally purports to assert PRC jurisdiction over aircraft in international airspace.22 Under international law, all transiting aircraft are guaranteed freedom of overflight in international airspace seaward of the territorial sea.

The PRC zone directly overlaps with those of Taiwan, South Korea, and Japan.23 This was the first ADIZ to intentionally overlap with another.24 It also includes airspace over the Japanese-administered Senkaku Islands adjacent to Taiwan. These islands are the subject of a territorial dispute between the PRC/Taiwan and Japan.25

Both the United States and Japan protested the establishment of the ECS ADIZ. Then-U.S. Secretary of State John Kerry accused China of attempting to change the status quo in the East China Sea and increasing tensions in the region. The U.S. statement further indicated that the United States does not “support efforts by any state to apply its ADIZ procedures to foreign aircraft not intending to enter its national airspace.” Japan’s Minister of Foreign Affairs similarly accused China of attempting to change the status quo in the East China Sea, indicating that the ADIZ “measures unduly infringe the freedom of flight in international airspace…and will have serious impacts on the order of international aviation.” Japan also objected strongly to the inclusion of the airspace over the Senkaku Islands within the ECS ADIZ.

Name

Lateral Limits

 Upper/Lower Limits and
system/means of activation announcement
INFO for CIV FLT
1 2
PRC ADIZ

3º11’N and 121º47’E , 33º11’N and 125º00’E, 31º00’N and 128º20’E, 25º38’N and 125º00’E, 24º45’N and 123º00’E, 26º44’N and 120º58’E

 UNL / SFC
Figure 1: East China Sea Air Identification Zones

Taiwan’s ADIZ is defined in its AIP.26 The Taiwan ADIZ was established by the United States after the Second World War and applies the standard request for aircraft entering the zone intending to enter Taiwanese air space to identify themselves. Civil aircraft are required to fly above 4,000 feet along designated airways or as vectored by air traffic controllers. Aircraft that do not comply with these requirements are subject to intercept by military aircraft.27 Other examples for intercept include, “Aircraft deviat[ing] from the current flight plan – fail[uire] to pass over a compulsory reporting point within 5 minutes of the estimated time over that point; deviat[ing] 20 NM from the centerline of the airway; or 2000FT difference from the assigned altitude; or any other deviations.”28 Taiwan’s AIP publishes strict guidance for aircraft to “fly straight and level” upon interception and to take no action that might be viewed as hostile. Communication with the intruding aircraft will be attempted via radio or visual signals. The AIP notes that Taiwan will not be held responsible for damages caused by interception or failure to comply with ADIZ requirements. Since September 2020, Chinese military aircraft have maintained a near continuous presence in the Taiwan ADIZ, penetrating the zone nearly 2,200 times. Although China believes that these incursions are consistent with international law because Taiwan is part of China, Taiwan has stated that it will respond in self-defense if attacked.

Name

Lateral Limits

 Upper/Lower Limits and
system/means of activation announcement
INFO for CIV FLT
1 2
Taiwan ADIZ
210000N 1173000E –
210000N 1213000E –
223000N 1230000E –
290000N 1230000E –
290000N 1173000E –
210000N 1173000E.		 UNL / SFC

The South Korean ADIZ is described in its AIP.29 The ADIZ was established in 1951 by the U.S. Air Force during the Korean War. It currently includes airspace above Ieodo/Suyan, a submerged feature disputed between South Korea and the PRC. South Korea expanded its ADIZ to include the airspace over Ieodo in December 2013 after the PRC included the airspace above the feature in its ADIZ in November 2013.30 The Korean ADIZ is similar to the PRC ADIZ in that it requires aircraft flying in the zone to submit a flight plan whether or not they intend to enter Korean air space. Aircraft are required to maintain two-way radio contact, use a secondary surveillance radar transponder, and make position reports every thirty minutes to air traffic control. 

An illustration of Japan’s ADIZ is contained in its AIP.31 Japan’s ADIZ was established in 1969. It does not include the airspace above the disputed Northern Territories/Kuril Islands controlled by Russia.32 The Japanese ADIZ follows the North American example applying its procedures only to aircraft intending to enter Japanese national airspace. The zone is divided into an inner and outer zone. The inner zone overlaps the territorial Sea of Japan. An aircraft entering the inner zone is expected to file a flight plan in advance and comply with air traffic control instructions or face interception.

Name and lateral limits Upper limit / Lower limit
1 2
KOREA ADIZ(KADIZ)

3900N 12330E – 3900N 13300E-

3717N 13300E – 3600N 13030E-

3513N 12948E – 3443N 12909E-

3417N 12852E – 3230N 12730E-

3230N 12650E – 3000N 12525E-

3000N 12400E – 3700N 12400E-

3900N 12330E

 UNL/SFC
Figure 2: Air Defense Identification Zone of Japan

Conclusion

While ADIZs may have once been a relic of the Cold War, the situation in the East China Sea has seen an increase in their use. As the issue of China-Taiwan relations remains unresolved, the PRC ADIZ might become a tool to pressure other nations if the PRC chooses to assert sovereignty over the ADIZ by intercepting civil aircraft over the ECS. Certainly for Taiwan, repeated instances of Chinese military aircraft testing Taiwan’s response time show that ADIZs will remain relevant for the foreseeable future.

LtCol Brent Stricker, U.S. Marine Corps, serves as the Director for Expeditionary Operations and as a military professor of international law at the Stockton Center for International Law at the U.S. Naval War College. The views presented are those of the author and do not necessarily reflect the policy or position of the U.S. Marine Corps, the U.S. Navy, the Naval War College, or the Department of Defense.

Endnotes

1. Convention on International Civil Aviation, Oct 13, 1919, 11 LNTS 174, reprinted in 17 AJIL Supp. 195 (1923) (no longer in effect).

2. Peter A. Dutton, “Caelum Liberum: Air Defense Identification Zones outside Sovereign Airspace” The American Journal of International Law, Vol. 103, No. 4 (Oct., 2009), pp. 691-709, 692.

3. Chicago Convention Article 3.

4. Id.

5. INT’L Civil Aviation Organization, Convention on International Civil Aviation, Annex 15, International Standards and Recommended Practices, Aeronautical Information Services (16th ed. July 2018). .

6. For a comprehensive listing of AIPs see Hazy Library Emory Riddle Aeronautical University Unmanned Aircraft Systems (UAS) Resources: Electronic AIPs by Country (https://erau.libguides.com/uas/electronic-aips-country).

7. James Kraska and Raul Pedrozo International Maritime Security Law 158 (2013); Raul “Pete” Pedrozo, “Air Defense Identification Zones” 97 INT’L L. STUD. 7, 8 (2021).

8. Joëlle Charbonneau, Katie Heelis, and Jinelle Piereder, “Putting Air Defense Identification Zones on the Radar” Centre for International Governance Innovation POLICY BRIEF No. 1 • June 2015 CIGI Graduate Fellows Series at 2

9. J Ashley Roach “Air Defense Identification Zones” Max Planck Encyclopedia of Public International Law www.mpepil.com, https://opil-ouplaw-com.usnwc.idm.oclc.org/view/10.1093/law:epil/9780199231690/law-9780199231690-e237; Each country’s ADIZ is defined in its own Aircraft Information Publication (AIP). Joëlle Charbonneau, Katie Heelis, and Jinelle Piereder, “Putting Air Defense Identification Zones on the Radar” Centre for International Governance Innovation POLICY BRIEF No. 1 • June 2015 CIGI Graduate Fellows Series at 4.

10. J Ashley Roach “Air Defense Identification Zones” Max Planck Encyclopedia of Public International Law www.mpepil.com, (https://opil-ouplaw-com.usnwc.idm.oclc.org/view/10.1093/law:epil/9780199231690/law-9780199231690-e237).

11. J Ashley Roach “Air Defense Identification Zones” Max Planck Encyclopedia of Public International Law www.mpepil.com, (https://opil-ouplaw-com.usnwc.idm.oclc.org/view/10.1093/law:epil/9780199231690/law-9780199231690-e237).

12. Chicago Convention Article 3.

13. Oliver J. Lissitzyn “Legal Implications of the U-2 and RB-47 Incidents” The American Journal of International Law Jan 1962, Vol 56, No.1 pp. 135-142. (https://www.cambridge.org/core/journals/american-journal-of-international-law/article/some-legal-implications-of-the-u2-and-rb47-incidents/EF3BFC9B45E842B3A5B298D120DBE241).

14. Lissitzyn at 141 (https://www.cambridge.org/core/journals/american-journal-of-international-law/article/some-legal-implications-of-the-u2-and-rb47-incidents/EF3BFC9B45E842B3A5B298D120DBE241).

15. Lissitzyn at 142 (https://www.cambridge.org/core/journals/american-journal-of-international-law/article/some-legal-implications-of-the-u2-and-rb47-incidents/EF3BFC9B45E842B3A5B298D120DBE241).

16. Joëlle Charbonneau, Katie Heelis, and Jinelle Piereder, “Putting Air Defense Identification Zones on the Radar” Centre for International Governance Innovation POLICY BRIEF No. 1 • June 2015 CIGI Graduate Fellows Series at 4.

17. “Strauss at 759; “Announcement of the Aircraft Identification Rules for the East China Sea Air Defense Identification Zone of the P.R.C.,” PRC Ministry of National Defense, November 23, 2013, (http://eng.mod.gov.cn/Press/2013-11/23/ content_4476143.htm).

18. To access the PRC AIP (https://www.aischina.com/EN/indexEn.aspx).

19. Ted Adam Newsome, “The Legality of Safety and Security Zones in Outer Space: A Look to Other Domains and Past Proposals” A thesis submitted to McGill University in partial fulfillment of the requirements of the degree of MASTER OF THE LAWS (LL.M.) Institute of Air and Space Law McGill University, Faculty of Law Montreal, Quebec August 2016 at 47.

20. “Pedrozo at 9-10.

21. Edmund J. Burke and Astrid Stuth Cevallos, In Line or Out of Order? China’s Approach to ADIZ in Theory and Practice 6-7 (2017).

22. Edmund J. Burke and Astrid Stuth Cevallos, In Line or Out of Order? China’s Approach to ADIZ in Theory and Practice 7 (2017).

23. Raul “Pete” Pedrozo, “China’s Legacy Maritime Claims” Lawfare (July 15, 2016) (https://www.lawfareblog.com/chinas-legacy-maritime-claims).

24. Raul “Pete” Pedrozo, “China’s Legacy Maritime Claims” Lawfare (July 15, 2016) (https://www.lawfareblog.com/chinas-legacy-maritime-claims).

25. Edmund J. Burke and Astrid Stuth Cevallos, In Line or Out of Order? China’s Approach to ADIZ in Theory and Practice 1 (2017).

26. To access Taiwan’s AIP (https://eaip.caa.gov.tw/eaip/home.faces).

27. NR 1.12 Taiwan AIP.

28. NR 1.12 Taiwan AIP.

29. To access the South Korea AIP (https://aim.koca.go.kr/aim/main.do).

30. Michael Strauss “China-Japan-South Korea-Taiwan: East China Sea Air Defense Identification Zones” Border Disputes : A Global Encyclopedia: Functional Disputes, 2015, p.759-764, 761.

31. To access Japan’s AIP (https://aisjapan.mlit.go.jp/Login.do).

32. Edmund J. Burke and Astrid Stuth Cevallos, In Line or Out of Order? China’s Approach to ADIZ in Theory and Practice 5 (2017).

Featured Image: U.S. Air Force, Navy, Marine Corps and Air Self-Defense Force aircraft conduct a large-scale joint and bilateral integration training exercise on Tuesday in airspace near Japan. (U.S. Air Force photo)

Law of Warfare

Expeditionary Advanced Base Operations: National Security Law at the Operational Level of War

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By Peter C. Combe II

In a recent piece for the Center for International Maritime Security (CIMSEC), Brent Stricker provided an excellent overview of legal considerations associated with the Marine Corps’ Force Design 2030, concepts for Stand-in-Forces (SIF) and Expeditionary Advanced Base Operations (EABO). Stricker provides a cogent introduction to targeting, deception and distinction questions if using non-standard platforms, and access, basing, and overflight (ABO) of regional states in the Pacific and South China Seas. This essay is intended to expand on additional legal considerations that the School of Advanced Warfighting student class of Academic Year 2022 encountered during the last year of study.

The Marine Littoral Regiment (MLR) is the Marine Corps’ contribution to the SIF concept. Foundational to the SIF concept is the ability to operate and persist within the enemy’s weapons employment zone (WEZ). In seeking to operate and persist within contested spaces, SIF need not always be Special Operations Forces (SOF), but in many ways they must be SOF-like. This includes not only size, and employment concepts, but enabling capabilities and the attendant authorities as well. 

Target Engagement Authority and Criteria

In addition to discussions of the ground, air, and maritime domains a discussion of the legal rules, and authorities associated with other domains and capabilities is relevant to the SIF concept. As important as what the U.S. Joint Force is legally permitted to do, is the question of the level at which those authorities lie.

Cyberspace presents a number of challenges to applying the Law of Armed Conflict (LOAC) because the United States and China hold different views about how it applies to cyberspace. The official U.S. position is that cyberspace operations can rise to the level of an armed attack if they have sufficient effects or impact systems of sufficient national importance, while the People’s Republic of China (PRC) takes a contrary stance, that LOAC (as a jus in bello matter) is inapplicable in cyberspace. Related is the determination of when and whether a cyberspace operation may rise to the level of an armed attack which justifies the use of force in self-defense pursuant to the U.N. Charter. While the United States and many other nations believe that a cyberspace operation may pose a sufficient jus ad bellum justification for self-defense, the PRC has remained silent on the matter. These divergent views on the jus ad bellum and jus in bello applicability in cyberspace pose the danger of miscalculation, which operational planners and national security practitioners must remain wary of.

The PLA Strategic Support Force (PLASSF) is the primary PLA organization tasked with the conduct of cyberspace operations. In a crisis situation it is possible that the PLASSF may seek to impose cyberspace effects on U.S. naval vessels in the South or East China Seas as a means of demonstrating resolve and on the rationale that such actions could not violate international law, as international law is inapplicable to cyberspace actions. However, the United States may view such an offensive cyberspace operation as equivalent to a use of force against a military vessel, and conclude that the right to use military force in self-defense pursuant to Article 51 of the U.N. Charter has been triggered.

In a deeper discussion of targeting, regardless of domain, we must also address who is authorized to engage a given target. For instance, where does the authority lie to employ various capabilities or to achieve certain effects? During the past 20 years of counterterrorism operations the authority to employ lethal fires was often held at the General/Flag Officer (GO/FO) or Joint Task Force (JTF) level. There were sound reasons for this including the operational imperative to limit civilian casualties and the tactical and operational patience required when dealing with a non-state actor on the other side of the globe. However, requiring GO/FO approval to employ lethal fires may be inappropriate when dealing with Expeditionary Advanced Base Operations (EABO) or Distributed Maritime Operations (DMO) in a communications denied/degraded environment against a near peer competitor. 

Degraded communications may prevent distributed tactical units from being able to contact a GO/FO to approve a strike. Similarly, the decision speed required may preclude the ability to fire effectively in modern salvo combat if a tactical unit is required to work through a Joint or Combined Task Force headquarters to take offensive strike decisions. Successful fires in a salvo combat model may require that an MLR Company Commander (i.e., a Marine Captain or Major) be authorized to approve offensive strikes against a PLA-Navy surface combatant.

A similar concern is the need to rely upon allies and partners for access, basing, and overflight (ABO) in any conflict in the Western Pacific. In those instances, the question is likely to arise: which allies and partners, or what other persons or infrastructure are U.S. forces permitted to use lethal force to defend? It is not uncommon for U.S. forces to be permitted to defend a particular partner while that partner is conducting one type of mission, but not others. Similarly, it is common that U.S. forces may be permitted to defend a partner force against some third party actors, but not others.

While national and tactical self-defense often includes the concept of collective self-defense, it is not something the Joint Force can take for granted. It may raise concerns about facilitating indiscriminate lethal targeting by an ally, or being drawn into a wider conflict, and thus limiting the circumstances under which U.S. forces may defend Saudi or Yemeni allies. It could generate concerns about the appropriate degree and level of support to non-state proxies and their compliance with international law. Congressional skepticism has also arisen based on the perception that U.S. forces use “collective self-defense” as a means to skirt Congressional authorizations to use military force. These are difficult questions – and what is operationally expedient may not be politically tenable. Operational planners must be prepared to scope self defense/collective self-defense rules of engagement to manage a number of competing tensions: what is legally permissible, what best serves operational requirements, and what is politically and diplomatically feasible. 

Aside from questions about the operational or tactical echelon at which targeting decisions are made, is the human commander’s role in those decisions. Artificial intelligence holds both enormous promise to increase the speed and quality of decision-making, while raising thorny ethical and quasi-legal questions about automation in decisions to use lethal force. Should artificial intelligence work primarily as a decision support tool, or with a “man-on-the-loop” for primarily defensive systems? This discussion is particularly pertinent when considering the possibility that the Marine Corps’ Marine Littoral Regiment (MLR) may be incorporated into the Navy’s Composite Warfare Command (CWC) structure – perhaps using a virtualized version of the Navy’s Aegis Combat System, which enables autonomous defensive engagements based on preset criteria. The Aegis Combat System may also permit automated offensive engagement in certain narrow circumstances.

These capabilities raise the possibility that an MLR/EAB commander may not be the final authority making firing or target decisions. Depending upon the availability of communications, and the MLR’s position within the CWC construct, the MLR may turn into essentially a maintenance and maneuver package for a Navy fires asset. It is further foreseeable that firing decisions are made not by a human (Navy or Marine Corps) commander, but made by automated systems and monitored by naval commanders and staff. 

Signature Management:
TAC-D, DISO, Joint MILDEC, Cover, or Something Else?

Signature management and deception also pose challenges, because responsibility to distinguish one’s own forces from civilians is borne by both attackers and defenders. Thus, signature management, including various levels of deception becomes both an imperative and a potential stumbling block. In addition to the distinction issues raised by Stricker’s article, there are administrative and policy requirements that the national security law practitioner must consider. Do certain signature management practices constitute Tactical Deception (TAC-D), Deception in Support of Operational Security (DISO), or Joint Military Deception (MILDEC)?

TAC-D is generally deceptive activity executed at the tactical level of command, for the purpose of influencing enemy commanders to take or forego actions favorable to achieving tactical level outcomes (battles and engagements). DISO targets adversary intelligence services rather than commanders or decision-makers, and seeks to create false indicators or observables that disguise or manipulate the true nature of a unit. Joint MILDEC sits atop the deception pyramid, is a theater level activity to support a Joint campaign, and is normally planned, approved, and conducted at the Combatant Command level in advance of and during a campaign. These are different, and not terribly well understood concepts within the larger Joint Force, and are approvable at different levels of command. Operational planners and national security law practitioners must understand the differences and most importantly the approval levels and timelines, as approving executions in support of Joint MILDEC may take months and require Joint Staff coordination prior to execution.

Other administrative signature management practices may prove no less challenging. The concept of “21st century foraging,” is pitched as a means to help Marine units persist within the PLA weapons employment zone (WEZ) without Joint Force or Marine Expeditionary Force (MEF) level logistics. As the PRC continues aggressive efforts to court (and coerce) neighboring countries, it is likely to attempt expansion of its cashless surveillance economy into those countries as well. In these instances, the use of cash may prove untenable and use of government associated credit cards may provide an easily traceable administrative signature. Attempts to use non-attributable credit accounts may implicate the need to staff and approve a cover or cover support plan, which can take significant amounts of time and resources, and will require coordination, approval, and resourcing from outside of Marine operating forces. Operational planners and national security law practitioners at the MEF, MARFOR, and Geographic Combatant Command (GCC) level must familiarize themselves with these concepts to make EABO and DMO feasible.

National Command Authority and Jus Ad Bellum

Other law of armed conflict considerations, more appropriate for the Joint Staff or National Command Authority, also bear consideration. A common scenario in discussions of EABO and SIF is the defense of Taiwan by U.S. forces. Operational planners and national security law practitioners need to understand that the U.S. abrogated the mutual defense treaty with Taiwan (the Republic of China / ROC) in 1979 as part of U.S. efforts to establish diplomatic relations with the PRC. The Taiwan Relations Act (TRA, passed the same year) also does not provide a domestic legal obligation to defend Taiwan, nor an international legal basis to do so. Rather, the TRA permits the Departments of State and Defense to essentially treat Taiwan as a state for Foreign Military Sales and Security Cooperation purposes. This remains an important distinction as fewer than 20 countries recognize Taiwan diplomatically, a number which does not include the U.S. or any permanent member of the U.N. Security Council.

With this context in mind, international law recognizes three traditional justifications for the use of force internationally: (1) under a U.N. Security Council Resolution (UNSCR), (2) self-defense, including collective self-defense of a third party country, and (3) consent of the state in whose territory force is used. The first and last justifications are non-starters in a Taiwan scenario as the PRC is a permanent member of the U.N. Security Council able to veto any potential UNSCR, and the U.S. “one China policy,” affords diplomatic recognition to the PRC in Beijing, not the ROC in Taipei.

Collective self-defense as a jus ad bellum justification is also typically applied to states, and unlikely for the reasons above. The U.S. has also never adopted the “responsibility to protect (R2P),” doctrine as an independent legal basis justifying the use of force in a third country to defend a non-state entity as a means to alleviate internal/domestic violations of International Human Rights Law (IHRL). Furthermore, recent events have called into question the degree to which the R2P doctrine may be falling out of favor in international law circles in the wake of Russia’s pretextual use of the doctrine to justify an aggressive war against Ukraine. However, that may not foreclose the discussion. An under-studied area of law with respect to international law justification is that of executive prerogative.

Presidential prerogative has a long history in the United States, with the country’s earliest presidents arguing over the contours of what the doctrine permitted, and whether or how those actions must be corrected or remedied after the fact in the absence of Congressional authorization. The concept of executive, or “Crown Prerogative,” also has a place in current and former English Commonwealth countries. Sir William Blackstone, the eminent 18th Century British jurist and legal commentator, described it separate and apart from the executive authority to administer the laws passed by Parliament. Because the U.N. Charter is not to the prejudice of Customary International Law (CIL) but rather acts as a sort of augment to existing CIL rules, the concept of executive prerogative may survive in some form as a distinct customary international legal basis to use force (or seize necessary territory) in a third country. These are questions that bear exploration as they relate to EABO specifically, and SIF more generally, especially in light of the President’s recent vow to use military force to defend Taiwan in the face of PLA aggression.

Furthermore, a core assumption of EABO and the Concept for Stand-in-Forces is the ability to operate from third countries in order to hold an adversary at risk. However, there is good reason to believe that many countries in the East and South China Seas will be reticent to ally with the U.S. during an armed conflict. In that case, is the U.S. then precluded from operating in those countries absent a non-consensual occupation of territory? The underlying question in this instance, obligations of an occupying power aside, is whether sovereignty is a rule of international law, or a foundational precept – but NOT a rule – underlying other international legal obligations. This question, combined with the question about presidential and executive prerogative, potentially bears great importance to the future success or failure of EAB operations in the event of armed conflict in the Western Pacific.

Conclusion

The EAB, DMO, and SIF concepts hold a degree of promise for peace time and conflict operations in the littorals and other contested maritime domains. Operational planners and national security law practitioners at the operational level of war must be familiar not only with the legal rules regarding targeting, deception, and signature management, but they must also understand where the authorities do (and should) lie with respect to those activities. They also need to understand how targeting practices have been adopted and adapted during 20 years of counterterrorism and counterinsurgency, both from a policy and law perspective. The time may soon arrive when authorities, capabilities and effects which were the domain of a GO/FO commander at a JTF are held at the battalion or even lower level.

Furthermore, U.S. forces will require ABO in third countries in the event of conflict heavily leveraged in the maritime domain, geography demands it no matter which ocean is host to the conflict. Consent from those third countries may be forthcoming, but others may remain reticent or even hostile to accede to U.S. requirements for ABO. Further exploration and understanding of legally available options for non-consensual operations (including lethal operations) is required to assure that ABO and enable effective employment of the new-look Marine Corps.

Lieutenant Colonel Combe is currently assigned to Judge Advocate Division, Headquarters Marine Corps. He recent’y graduated as a resident student at Marine Corps University’s School of Advanced Warfighting. His operational law experience includes serving in the International and Operational Law Branch, Judge Advocate Division and numerous operational deployments in support of conventional and special operations across multiple Combatant Commands. He has written several articles and blog posts on national security law.

The views presented are those of the author and do not necessarily represent the views of the Department of Defense, the Marine Corps, or any other military or government agency.

Featured Image: OKINAWA, Japan (July 8, 2022) – Reconnaissance scouts assigned to the Maritime Raid Force, 31st Marine Expeditionary Unit wait for a UH-1Y Venom to land during a tactical air control party training on Irisuna Island, Okinawa, Japan, July 8, 2022. (U.S. Marine Corps photo by Sgt. Andrew King)