Hybrid Threats and Grey Zone Conflict Symposium – Challenges in the Twilight of International Law

Editors note: The following post highlights a chapter that appears in Mitt Regan and Aurel Sari’s recently published book Hybrid Threats and Grey Zone Conflict: The Challenge to Liberal Democracies. For a general introduction to the series, see Prof Mitt Regan and Prof Aurel Sari’s introductory post.

As full-scale wars are currently underway in Ukraine and Gaza, the grey zone may not seem to be a prominent problem of international law. Nevertheless, national defense must be ready for a full spectrum of conflict escalation. Grey zone operations remain a credible threat to the security and stability of international relations. The threat is real, especially in the Indo-Pacific region, as the People’s Republic of China (PRC) increases its military activities and expands its influence in other parts of the world.

Grey zone strategy is a cost-efficient option to advance national interests over a disputed territory or waters by forceful presence or incursion, without risking open conflict involving confrontation of military forces. Consider the political and economic costs inflicted on Russia when it annexed Crimea as a result of the grey zone operation it conducted in 2014. These costs were negligible compared to those of the full-scale armed confrontation that Russia started in February 2022.

A malicious actor could use grey zone operations over time to sustain persistent threats and ultimately achieve a fait accompli with minimum adverse impacts. Furthermore, even in situations of open armed confrontation, a belligerent could employ grey zone operations against other States that are not directly engaged in the armed conflict. Such operations could prove useful and effective to deter other States from taking collective or concerted action. A belligerent could also use grey zone operations as an instrument of obfuscation to keep other States at bay while focusing conventional military capabilities in the theater of combat.

Ultimately, the exploitability of the grey zone is a manifestation of structural problems of international law. Existing legal frameworks are built on different legal standards and criteria to classify situations and determine the legality of action. Each of these rules has been developed independently without a centralized process of law-making, which has in turn created opportunities exploitable by malicious actors. Modern innovations, such as information technology and artificial intelligence-enabled deep fake technology, exacerbate this problem by giving clandestine actors the ability to deny or better conceal their involvement. My contribution to the recent publication of Hybrid Threats and Grey Zone Conflict delves into these structural problems of international law that contribute to the growth of hybrid threats as a strategic choice of hostile actors.

Rather than summarizing my argument, this post illustrates how these structural flaws of international law affect the law of armed conflict (LOAC)—jus in bello—and its implementation in grey zone conflicts. It does so by highlighting two distinct challenges to LOAC when three conditions I have identified in the book chapter are present for strategic exploitation: hostile actors targeting a law-compliant State; the use of non-State proxies for hostile purposes; and reliance on advanced technological capabilities and enablers.

Applicability of LOAC Rules

“Grey zone” is a term that generally describes a conflict falling between peacetime competition and armed conflict. In strategic terms, it refers to subthreshold competition and persistent campaigns that stay below the threshold that would cause a war to break out. In legal terms, this concept translates into the classification of conflicts, with different legal thresholds that trigger relevant normative concepts, such as a threat or use of force prohibited under Article 2(4) of the UN Charter or an international armed conflict to which LOAC applies.

Identifying the applicable legal framework is critical to ensuring the legality of response actions against a grey zone operation where an adversary has shrouded its hostile activities in legal ambiguities. LOAC, if applicable, not only prohibits certain conduct and imposes restrictions (e.g., not to direct attacks against civilians) but also provides the source of legal authority to conduct hostilities (e.g., may direct attacks against military objectives). In countries that embrace respect for the rule of law, this legal authority derived from international law is integrated into the domestic legal structures and processes through which the political assessment of a situation cascades through the chain of command.

With hybrid threats, a hostile actor can exploit the legal uncertainty surrounding conflict classification to restrict legally viable options available to the defending State. When the threat involves the conduct of non-State actors, such as maritime militia and terrorist organizations, the existence of an international armed conflict is not obvious. This is because, as the International Criminal Tribunal for the former Yugoslavia (ICTY) established in the Tadić case, their conduct does not trigger an international armed conflict unless the State exercises overall control over the group, “not only by equipping and financing the group, but also by coordinating or helping in the general planning of its military activity” (para. 131). The State employing hybrid threats can deny the international character of the confrontation by deliberately concealing the nature and level of assistance it provides for a group of individuals as they mount a hostile campaign against the foreign target. Conflicting assessments of Israel’s confrontation with Iran illustrate this challenge.

The defending State may pursue another option by characterizing the situation as a non-international armed conflict under common Article 3 of the 1949 Geneva Conventions. However, the ICTY in Tadić and subsequent rulings by international courts and tribunals have determined that this classification is only available when non-State actors engage in “protracted armed violence” with some degree of organization. Thus, if a hostile actor deliberately repeats isolated and sporadic acts of violence, hybrid threats could stay below the requisite threshold of intensity. In such a situation, the defending State will have no choice but to limit itself to law enforcement action to which various restrictions apply under international human rights law or, in the maritime context, under Article 225 of the Law of the Sea Convention, as derived from judicial and arbitral decisions (§ 3.11.5). If its domestic law or policy imposes stricter restrictions on the use of force in law enforcement, the State will find itself more vulnerable to these hybrid threats.

On top of these legal threshold issues, political and strategic concerns about the risk of conflict escalation may impede the defending State’s ability to respond to hybrid threats in a timely and effective manner. Modern technology enables self-organized militia to engage in hostilities at various levels of intensity in different domains, such as maritime and cyberspace. These hybrid threats put law-compliant countries on the back foot as their response options are regulated within existing legal frameworks that are not flexible enough to allow for escalating the mode of operation as appropriate to the level and type of hostilities they encounter.

Legal Characterization of Hostile Action

Because the international legal system is decentralized, each State may differently characterize factual circumstances as falling within a particular legal framework. The legal characterization offered by a State does not necessarily control and may well be challenged by other States or overturned by an international court or tribunal. Nonetheless, in the absence of a centralized law enforcement mechanism, each State has great sway over how its actions should be legally characterized. Awareness of this reality in international relations is critical to the understanding of grey zone conflicts.

The PRC, for example, has been exploiting legal vocabularies, such as sovereignty and historic rights, to gain strategic advantage and assert political legitimacy over broad maritime claims within the so-called “Nine-Dash Line.” The PRC has continued to do so despite the fact that an Arbitral Tribunal found the application of these concepts invalid. In 2021, the PRC government enacted the new Coast Guard Law to legitimize maritime enforcement action against foreign-flagged vessels operating within the broadly and vaguely defined “waters under China’s jurisdiction.” On this basis, Chinese coast guard vessels have been conducting hostile actions against Philippine vessels attempting a resupply of Sierra Madre, a Philippine Navy transport vessel that remains aground on the Second Thomas Shoal. The use of non-lethal weapons and tactics such as laser, water cannons, and ramming indicates their intention to stay below the thresholds of armed conflict.

These grey zone operations could be pushed further to penetrate the realm of armed conflict where hostile engagement must comply with LOAC. Hostile actors may continue to target civilians and civilian vessels or prosecute members of foreign armed forces under the guise of law enforcement to defy their LOAC obligations. Indeed, when the Russian coast guard captured Ukrainian sailors on board three Ukrainian naval ships near the entrance to the Kersh Strait in November 2018, these sailors were denied protection as prisoners of war but instead were criminally charged and ill-treated by Russian law enforcement authorities (p. 21–22). Although ultimately released during an exchange of prisoners in September 2019, this episode demonstrates how existing legal frameworks are vulnerable to strategic exploitation when there is no political incentive to recognize the protections accorded under LOAC.

Concluding Thoughts

The current structure of international law was devised to manage international relations when sovereign States were the predominant actors that controlled the use of force. Technological advances and non-State actors’ increased ability to unleash a high degree of destructive force revealed flaws within international law’s structure, some of which have afforded malicious actors the opportunity for exploitation to advance their strategic gains. As a sovereignty-based legal regime, international law’s normative value and effectiveness depends primarily on its national implementation in good faith. Its credibility as an instrument to manage international relations declines as a greater number of States start taking advantage of these flaws by engaging in proxy wars or by exploiting the adversary’s respect for the rule of law.

My contribution to the latest volume on hybrid threats and grey zone conflicts is an attempt to decipher the mechanism of these threats from a legal perspective. But understanding the causes of the problem is only the first step to fixing it. Merely advocating for compliance with international law or imposing sanctions does not help address the root causes of the problem. International law as a political project has suffered setbacks over the last decade. It is likely to decline further if these structural problems continue to pose challenges to the rules-based international order.

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Hitoshi Nasu is a Professor of Law in the Department of Law at the United States Military Academy.

Photo credit: BelTA News Agency