Category Archives: Law of Warfare

East China Sea Air Defense Identification Zones: A Primer

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)

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

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)