Law Commons^™

Cyberspace And The Jus Ad Bellum: The State Of Play, Michael N. Schmitt, Anusha S. Pakkam

International Law Studies

This article examines how States are interpreting one aspect of the international law governing cyber activities, the jus ad bellum. The article focuses on two issues: (1) the prohibition on the use of force found in Article 2(4) of the UN Charter, and (2) the right of self-defense in Article 51. The critical unsettled question regarding the first issue is the threshold at which a hostile cyber operation can be characterized as a “use of force” subject to the prohibition of Article 2(4). Concerning the second issue, a number of unresolved questions plague the application of the right of …

“Unwilling Or Unable”, Lucy V. Jordan

International Law Studies

Critics of the unwilling or unable doctrine suggest that it could undermine the United Nations collective security system and argue that it requires an unacceptable ceding of a State’s territorial sovereignty. Increased reliance on the doctrine following the terrorist attacks of 9/11, particularly in relation to the use of force against ISIL in Syria since 2014, has caused the doctrine to face significant scrutiny. The purpose of this article is to ascertain whether the unwilling or unable doctrine has reached customary international law status. If found to be the case, the doctrine would confirm the right of States to act …

International Law And Acoustic Antagonism In East Asian Waters, Matt D. Montazzoli, John C. Tramazzo

International Law Studies

This article analyzes a 2023 maritime incident in which the Chinese Navy Ship (CNS) Ningbo employed active sonar in the vicinity of His Majesty’s Australian Ship (HMAS) Toowoomba, while knowing that Toowoomba had divers in the water. The Chinese sonar caused injuries to the Australian divers. The article discusses the employment of acoustic devices to cause harm during peacetime and analyzes whether CNS Ningbo’s actions constituted a failure of "due regard" and other applicable legal regimes and norms. The article concludes that CNS Ningbo’s actions were an unlawful use of force and failed to demonstrate due regard, and that …

Protecting The Free Flow Of Commerce From Houthi Attacks Off The Arabian Peninsula, Raul (Pete) Pedrozo

International Law Studies

This article reviews recent maritime incidents involving Houthi missile and drone attacks on commercial shipping and foreign warships off the Arabian Peninsula, purportedly in response to the Israeli military operations in Gaza following the October 7, 2023, Hamas-led attack that killed over 1,300 Israeli civilians. The article discusses the legality of the U.S. response to those incidents, including U.S. counter-piracy operations and the right of unit and collective self-defense. The article also discusses whether the United States should consider conducting land-based attacks on Houthi missile and drone sites in Yemen under the principle of self-help to preempt further attacks on …

Aid And Assistance As A “Use Of Force” Under The Jus Ad Bellum, Michael N. Schmitt, W. Casey Biggerstaff

International Law Studies

Although the prohibition of the use of force is a cornerstone of international law, our understanding of what constitutes a “use of force” under Article 2(4) of the UN Charter nonetheless continues to evolve. While the term was traditionally understood to mean armed force, emerging interpretations are expanding our understanding of the prohibition’s breadth. The Charter’s text, travaux préparatoires, and subsequent interpretations and practice by States, reinforced by the persuasive reasoning of the International Court of Justice, all confirm that the notion of force extends to indirect force, which includes military support provided to parties to a conflict. Yet, to …

Assessing The Legal Framework For Potential U.S. Conflict With China Over Taiwan, Shawn W. Brennan

International Law Studies

The People’s Republic of China has clearly stated the importance of resolving the Taiwan question and realizing China’s complete “reunification” to end their century of humiliation. As China grows as the most significant strategic competitor to the United States and develops the military capability to force the issue, understanding what legal authorities the President may exercise in ordering a response is increasingly urgent. This article reviews the legal authorities for the use of force by the United States and examines the contours of the President’s authorities and where they intersect with Congress’s authorities. Through various hypothetical scenarios involving attempts by …

Some Reflections On The Threshold For International Armed Conflict And On The Application Of The Law Of Armed Conflict In Any Armed Conflict, T.D. Gill

International Law Studies

This essay discusses the threshold of application of international humanitarian law (IHL) in both international (IAC) and non-international armed conflicts (NIAC). In relation to IAC it questions whether the International Committee of the Red Cross (ICRC) “first shot” approach is the most appropriate, since it opens the way for the intensification of conflicts beyond what is necessary in relation to relatively minor armed incidents and argues that the humanitarian protection clauses of IHL should be separated from the rules governing hostilities and makes a case for the application of ad bellum considerations of necessity and proportionality to act as a …

The Prohibition On Intervention Under International Law And Cyber Operations, Ori Pomson

International Law Studies

Given that cyber technologies have made way for attempts to influence the affairs of other States in novel and unique ways, scholars have turned to the international legal rule which is prima facie most relevant in addressing such meddling; namely, the prohibition on intervention. Moreover, there appears to be quite a wide-ranging consensus in scholarship that the prohibition on intervention applies to a broad range of cyber operations. In contrast to such scholarship, this article argues that, under the lex lata, the prohibition on intervention only applies to acts amounting to a use of force or constituting support for …

Targeting A Satellite: Contrasting Considerations Between The Jus Ad Bellum And The Jus In Bello, Hitoshi Nasu

International Law Studies

With the development and greater availability of counter-space capabilities, satellites are becoming a prime target of military threats. However, the legal assessment for the targeting of a satellite requires careful analysis because of its impacts on terrestrial activities and the potential to affect the rights and interests of third parties when their payloads are carried by the targeted satellite. With these two unique characteristics in mind, this article unravels the complexity of international legal regimes applicable to military operations conducted against a satellite by contrasting threshold legal considerations necessary for the identification and application of relevant legal requirements under the …

Cyber Peacekeeping Operations And The Regulation Of The Use Of Lethal Force, Nicholas Tsagourias, Giacomo Biggio

International Law Studies

Peacekeeping is an essential tool at the disposal of the United Nations for the maintenance of international peace and security. The growing relevance of cyber technologies presents itself as an opportunity to adapt peacekeeping to the challenges of a rapidly evolving security landscape. This article introduces the notion of "cyber-peacekeeping," defined as the incorporation and use of cyber capabilities by peacekeepers. It discusses the legal basis for cyber-peacekeeping and the foundational principles of consent, impartiality, and use of defensive force. The article examines the use of lethal force by cyber-peacekeepers under the law of armed conflict paradigm. It considers the …

Revisiting Ad Bellum Proportionality: Challenging The Factors Used To Assess It, Yishai Beer

International Law Studies

Traditionally, international law has established a binary distinction between jus ad bellum and jus in bello. The former relates to the right to exercise military force. The latter regulates the conduct of adversaries engaged in an armed conflict. However, the prevailing legal approach doesn't accept this dichotomy. It wants to reduce war's hazards by applying the ad bellum rules, including the proportionality requirement, continuously throughout the conduct of armed conflict. To that end, it has established factors that define the essence of the continuing ad bellum proportionality requirement. This article challenges the near-unanimous consensus regarding these factors. It argues that …

The Plea Of Necessity: An Oft Overlooked Response Option To Hostile Cyber Operations, Louise Arimatsu, Michael N. Schmitt

International Law Studies

States are increasingly focused on the measures—cyber or otherwise—that they can take in response to hostile cyber operations. Although cyber operations are usually responded to with acts of “retorsion” (acts that are lawful, although unfriendly), international law recognizes other self-help mechanisms that allow for more robust responses. In the cyber context, most attention has focused on countermeasures and self-defense. Yet, both are subject to various limitations that constrain their availability.

This article examines a further option, the so-called “plea of necessity.” It allows States to respond to a hostile cyber operation when the action taken would otherwise be unlawful but …

Cyber Attribution And State Responsibility, William Banks

International Law Studies

We might expect international law to specifically address cyber attribution requirements due to the significance of attribution in framing the legal responsibility of States and the boundaries of responsive actions by victim States. However, there is little international law of cyber attribution, and what law there is exists largely by implication. Likewise, there is only a murky and highly contested law of State responsibility that theoretically constrains the vast majority of State-sponsored cyberattacks. Because victim States cannot engage in countermeasures unless they attribute a cyberattack to a State, attribution can serve simultaneously to constrain and empower victim States. However, the …

Application Of The Due Diligence Principle To Cyber Operations, Tomohiro Mikanagi

International Law Studies

The discreet use of proxies by States renders it difficult to prove attribution to States under the existing rules of attribution. On the other hand, the due diligence principle, if applicable, does not require attribution but can lead to the invocation of State responsibility for cyber operations emanating from the territory of other States. In the Corfu Channel judgment the ICJ recognized “every State’s obligation not to allow knowingly its territory to be used for acts contrary to the rights of other States,” and UN Member States agreed that existing international law applies to cyber operations. However, the UN Members …

Legal Advisers In The Field During Armed Conflict, Yoram Dinstein

International Law Studies

Additional Protocol I to the Geneva Conventions of 1949 requires that legal advisers be made available to military commanders, particularly during hostilities. This treaty stipulation was quite innovative in 1977, but it has achieved widespread implementation, even among non-Contracting Parties. It is noteworthy that the United States—which objects to numerous provisions of Additional Protocol I—does not dissent from the article requiring legal advisers. A study of the practice of States, made by the International Committee of the Red Cross, confirms that the norm requiring that legal advisers be made available to advise military commanders in time of armed conflict currently …

Military Action To Recover Occupied Land: Lawful Self-Defense Or Prohibited Use Of Force? The 2020 Nagorno-Karabakh Conflict Revisited, Tom Ruys, Felipe Rodriguez Silvestre

International Law Studies

In September 2020, heavy fighting erupted between Armenia and Azerbaijan in and around Nagorno-Karabakh, a region of Azerbaijan long controlled by Armenia. After two months of military confrontations, a tripartite ceasefire was concluded, drastically altering the pre-existing territorial status quo.

The "Second Nagorno-Karabakh War" brings to light a fundamental question for international law on the use of force—and one that has received limited attention in legal doctrine. The question is this: when part of a State’s territory is occupied by another State for an extended period of time, can the former still invoke the right of self-defense to justify …

Developing International Guidelines For Protecting Schools And Universities From Military Use During Armed Conflict, Steven Haines

International Law Studies

One consequence of armed conflict, especially that of a non-international character, is serious damage done to vital societal infrastructure. Education–schools and universities–can be severely disrupted, even subject to attack. Targeting of schools may not invariably be unlawful if educational facilities are being put to military use. Such use may itself not be unlawful but it can result in schools being transformed from civilian objects into military objectives–and subject, therefore, to lawful targeting. This was a problem highlighted by humanitarian NGOs a decade ago and led to the formation, by both NGOs and United Nations agencies, of the Global Coalition to …

Protection Of Data In Armed Conflict, Robin Geiss, Henning Lahmann

International Law Studies

This article presents a novel way to conceptualize the protection of data in situations of armed conflict. Although the question of the targeting of data through adversarial military cyber operations and its implications for the qualification of such conduct under International Humanitarian Law has been on scholars’ and states’ radar for the last few years, there remain a number of misunderstandings as to how to think about the notion of “data.” Based on a number of fictional scenarios, the article clarifies the pertinent terminology and makes some expedient distinctions between various types of data. It then analyzes how existing international …

Legal Reviews Of War Algorithms, Tobias Vestner, Altea Rossi

International Law Studies

States and scholars recognize legal reviews of weapons, means or methods of warfare as an essential tool to ensure the legality of military applications of artificial intelligence (AI). Yet, are existing practices fit for this task? This article identifies necessary adaptations to current practices. For AI-enabled systems that are used in relation to targeting, legal reviews need to assess the systems’ compliance with additional rules of international law, in particular targeting law under international humanitarian law (IHL). This article discusses the procedural ramifications thereof. The article further finds that AI systems’ predictability problem needs to be addressed by the technical …

Maritime Police Law Of The People’S Republic Of China, Raul (Pete) Pedrozo

International Law Studies

China’s new Maritime Police Law (MPL) purports to regulate the duties of China’s maritime police agencies, including the China Coast Guard, and safeguard China’s sovereignty, security, and rights and interest. The MPL has potentially far-reaching application, as China claims extensive maritime areas off its mainland and in the South China Sea. This expansive application of maritime law enforcement jurisdiction is problematic given that most of China’s maritime claims are inconsistent with international law. To the extent that the MPL purports to assert jurisdiction over foreign flagged vessels in disputed areas or on the high seas, it contravenes international law. Numerous …

Command Accountability For Ai Weapon Systems In The Law Of Armed Conflict, James Kraska

International Law Studies

The use of artificial intelligence (AI) in weapon systems enhances the ability of operational forces to fuse multispectral sensors to understand the warfighting environment, positively identify, track, and select targets, and engage them with the most appropriate effects. The potential for AI to help close the “kill chain” has raised concern that this creates a gap in accountability between the decisions of humans and the acts of machines, with humans no longer accountable for decisions made during armed conflict. This study suggests that there is no gap because the military commander is always directly and individually accountable for the employment …

Israel’S Perspective On Key Legal And Practical Issues Concerning The Application Of International Law To Cyber Operations, Roy Schöndorf

International Law Studies

The speech given by the Israeli Deputy Attorney General (International Law) at the Naval War College’s event on “Disruptive Technologies and International Law” sets out, for the first time, Israel’s position on the application of international law to cyber operations. Consistent with the position taken by the vast majority of States thus far, Israel considers that international law applies to such operations. The speech stresses that questions pertaining to the identification and application of relevant legal rules remain, given the profound differences between the cyber domain and traditional domains of warfare—land, sea, and air. Therefore, in Israel’s view, a cautious …

Armed Conflicts In Outer Space: Which Law Applies?, Frans G. Von Der Dunk

International Law Studies

So far, outer space has merely become involved in terrestrial armed conflicts as part of the supportive infrastructure for military activities. Unfortunately, the risk that this changes is considerably growing, and it can no longer be excluded that (armed) force will become used in outer space, either directed towards Earth or within outer space itself.

This raises serious issues in the legal context, where space law so far has been premised on the hope that armed conflicts in outer space could be avoided whereas the law of armed conflict was not required so far to deal with the use of …

Responding To Hostile Cyber Operations: The “In-Kind” Option, Michael N. Schmitt, Durward E. Johnson

International Law Studies

Facing hostile cyber operations, States are crafting responsive strategies, tactics and rules of engagement. One of the major challenges in doing so is that key aspects of the international law governing cyber responses are vague, unsettled or complex. Not surprisingly, therefore, international law is markedly absent from strategies and operational concepts. Rather, they tend to take on a practical “tit-for-tat” feel as policymakers logically view “in-kind” responses as “fair play.” For them, responding in-kind surely must be lawful notwithstanding any challenges in discerning the precise legal character of the initial hostile cyber operation.

Testing that sense, this article examines the …

The Human Dimension Of Peace And Aggression, Chiara Redaelli

International Law Studies

Since the adoption of the Charter of the United Nations, the current international legal framework has drastically changed. In its traditional understanding, aggression is “the supreme international crime” aimed at protecting sovereignty and the territorial integrity of states. On the other hand, the U.N. Charter endorses an understanding of peace in the negative sense, that is, as mere absence of war. As human rights have gained momentum, they have helped reshape the legal landscape, a phenomenon referred to as the humanization of international law. How do peace and aggression fit within the humanized legal framework? This article will investigate the …

The Interplay Of International Obligations Connected To The Conduct Of Others: Toward A Framework Of Mutual Compliance Among States Engaged In Partnered Warfare, Berenice Boutin

International Law Studies

This article examines international obligations that arise in relation to the conduct of other States, and analyzes how they apply and interact in the context of partnered warfare. It investigates rules of State responsibility relevant to the context of partnered warfare, as well as primary norms that impose obligations connected to the conduct of others. In essence, they consist of obligations not to actively help to or to blindly let others do what a State would not do itself. It is argued that, taken together, these rules form the contour of an overarching framework of mutual compliance among States cooperating …

An Incident In The South China Sea, Rob Mclaughlin

International Law Studies

This article assesses characterization issues under the law of the sea, through the medium of an International Law Studies “maritime situation.” The article begins with a hypothetical scenario concerning an incident between a NATO warship and PRC vessels near Subi Reef and Thitu Island in the South China Sea. The analysis then turns to how we might assess characterization issues under the law of the sea as they apply to this incident. The lenses of analysis employed are: (1) Where, in law of the sea terms, did the incident happen? (2) Who, employing a law of the sea characterization scheme, …

Will Cyber Autonomy Undercut Democratic Accountability?, Ashley Deeks

International Law Studies

In recent years, legislative bodies such as the U.S. Congress and the U.K. Parliament have struggled to maintain a role for themselves in government decisions to conduct military operations against foreign adversaries. Some of these challenges arise from constitutional structures, but they are also due to the changing nature of conflict: a shift away from large-scale kinetic operations and toward smaller-scale operations—including cyber operations—that are less visible and that do not require robust legislative support. These modern operations leave legislatures to engage in ex post and sometimes ineffective efforts to hold their executive branches accountable for international uses of force …

Autonomous Cyber Capabilities Below And Above The Use Of Force Threshold: Balancing Proportionality And The Need For Speed, Peter Margulies

International Law Studies

Protecting the cyber domain requires speedy responses. Mustering that speed will be a task reserved for autonomous cyber agents—software that chooses particular actions without prior human approval. Unfortunately, autonomous agents also suffer from marked deficits, including bias, unintelligibility, and a lack of contextual judgment. Those deficits pose serious challenges for compliance with international law principles such as proportionality.

In the jus ad bellum, jus in bello, and the law of countermeasures, compliance with proportionality reduces harm and the risk of escalation. Autonomous agent flaws will impair their ability to make the fine-grained decisions that proportionality entails. However, a …

Special Rules Of Attribution Of Conduct In International Law, Marko Milanovic

International Law Studies

Are there are any special rules of attribution in international law? Are there, in other words, imputational rules that are not recognized as such in general international law, but are specific to particular branches of international law? This is the first article to systematically analyze the notion of special rules of attribution in international law. In particular, it searches for such rules in international humanitarian law, the law on the use of force, and European human rights law.

The article argues that, to the extent special rules of attribution exist, they are rare and never uncontroversial. In most situations, putative …