Based on the previous analysis (supra Chapter 5 of Part 2), it appears that under the current legal framework and case law a State might be somewhat paradoxically obliged to comply with Article 2(4) of the UN Charter in its response to such unlawful use of force in hybrid naval conflicts that does not meet the gravity threshold under the icj’s case law for it falling within the ambit of an armed attack. Clearly, the targeted State may employ force to protect itself against aggression by making use of law enforcement measures. However, this entails that its use of arms bears the risk of exceeding the limits of proportionality, the limits of which are significantly narrower in the law enforcement domain as compared to armed conflicts.
It would be desirable that international judicial bodies openly address this problem in their future case law. For example, if the Annex vii Arbitral Tribunal interprets the applicable law from the perspective of whether or not the Kerch Strait incident constituted (part of) an armed conflict between the two States or a law enforcement operation (possibly within an armed conflict), it would significantly contribute to increasing legal certainty over the legal categorisation of naval incidents that currently are often deemed as falling in a grey zone between the laws of peace and war.
Yet such expectations were also prevalent in relation to the icj’s proceedings in the Oil Platforms Case. As examined above, the icj’s judgment in the Oil Platforms Case is not particularly encouraging in confirming the hypothesis that the unclarity in the legal categorisation of incidents that have occurred in grey zones will gradually dissolve in the proceedings before international judicial bodies on a case-by-case basis. One may even wonder if the reason why we are debating the need for a legal framework of hybrid naval warfare is partly due to the icj’s judgment in the Oil Platforms Case.
In its judgment, the icj appears to have opened the door for hybrid naval warfare by, on the one hand, setting the threshold of an armed attack to a high level, while, on the other hand, narrowly interpreting the law of State responsibility. In this context, the Annex vii Arbitral Tribunal will hopefully provide its contribution to developing the jurisprudence on the legal framework applicable to the use of force in the maritime domain. Its on-going proceedings
If minor clashes between States are not considered to be an international armed conflict or if the very beginning of hostilities is not regulated by humanitarian law, one would have to identify an alternative in terms of the applicable law. Human rights law and domestic law do not seem to be equipped to deal fully with inter-State violence. For its part, the jus ad bellum provides a general framework on the lawfulness of the recourse to the use of force but contains only very general rules on the way force may be used. Once force is actually being used by one State against another, humanitarian law provides detailed rules that are well tailored to inter-State armed confrontations. It is therefore logical and in conformity with the humanitarian purpose of the Conventions that there be no requirement of a specific level of intensity of violence to trigger an international armed conflict.1
The concept of the most grave form of the use of force, as established in the jurisprudence of the icj, currently limits the right of self-defence in response to low-intensity warfare. This results in legal uncertainty, especially for the victim States, on how to respond to the low-intensity use of force by another State (e.g., the Kerch Strait incident). It contradicts with the aim that, as expressed by Gill and Fleck, “in order to be realistic and fair for combatants who need to make split-second decisions, the rules regulating the use of force must be clear and simple.”2
It seems that any proposal to enhance maritime security will have its drawbacks and its opponents. An incremental change in perspective is proposed here in relation to law enforcement powers rather than relying on expansive interpretations of the law on the use of force and the law of armed conflict. The latter raises legal conundra that extend well beyond questions of maritime security.3
This view predates the rapid rise of inter-State conflicts in the maritime domain in the past years. It was made in the context of the so-called ‘war on terror’ when the maritime security law was mainly challenged by non-State actors, in respect of whom the application of the law enforcement paradigm is well-founded. At the time, the legal challenges in maritime security were predominantly associated with terrorism and, to a somewhat lesser extent, with piracy.4 By contrast, in recent years, the main threats to maritime security have shifted away from terrorism and piracy. Instead, the world has returned to a so-called great power competition between major maritime powers and the accompanying inter-State naval conflicts.
This study has shown that in the past couple of years alone, there have been numerous inter-State conflicts (including the Yemeni armed conflict and the escalation of the Russia-Ukraine War in 2022) that have spread to the maritime domain. This is demonstrated by the 2018 Kerch Strait incident, 2019 limpet mine attacks in the Strait of Hormuz, attacks against international shipping in and around the Bab el-Mandeb in the broader framework of the Yemeni armed conflict, the recent hybrid naval warfare (‘shadow war’) between Iran and Israel, as well as the blockade of the Sea of Azov and attacks against neutral commercial ships in the Black Sea (both in 2022). In addition, 2021 marked growing tensions between the militaries and coast guards of China and Taiwan in the Taiwan Strait.
In the light of these developments, one may argue that instead of shifting the legal governance of such incidents to the purview of law enforcement that
icrc 2016 commentary, op. cit., on Common Article 2, para 243.
Gill and Fleck, op. cit., 82.
Klein, op. cit., 300.
See for example the various contributions to the collection of conference presentations, in MH Nordquist, R Wolfrum, JN Moore, R Long (eds.), Legal Challenges in Maritime Security (Brill, Leiden, Boston, 2008), 1–592.
Notably, the applicability of the law of naval warfare to non-international armed conflicts “is a contentious issue”. Heintschel von Heinegg 2016, op. cit., 211ff.
Gill and Fleck, op. cit., 73.