Does breaching UNCLOS invoke
the right of self-defence?
By Shani Friedman
Published on 19 February 2024
Introduction
Since October 2023, as part of the Israeli-Hamas war following the October 7 massacre in Israel, the Houthis – an Iranian-backed Yemeni terrorist group – attacked commercial ships in the Gulf of Aden and the Red Sea in support of Hamas. The attacks range from non-violent boarding and rerouting of ships to using missiles and drones.
Using force at sea may violate the 1982 United Nations Convention on the Law of the Sea (‘UNCLOS’). For example, the Bab al-Mandeb Strait is used for international navigation. All states have a right of transit passage through such straits, which cannot be suspended (UNCLOS, Art. 37-38, 44). However, UNCLOS is not the appropriate framework to deal with the situation as the Houthis are not bound by UNCLOS (UNCLOS, Art. 305). Additionally, these attacks cannot be considered as piracy, which grants states enforcement jurisdiction (UNCLOS, Art. 105, 110), as at least one of the conditions is not fulfilled. Piracy is defined as violent acts ‘for private ends’ (UNCLOS, Art. 101). Some argue that such ends are not limited to economic goals (e.g., here, here). Piracy could include acts for political purposes, such as those reflected in the Houthis statements. However, UNCLOS’s negotiating history indicates that piracy is for economic gains (e.g., here, para. 61; here, para. 11). This interpretation finds a precursor in the 1958 High Seas Convention, the provisions of which suggested that acts for political ends would not be regarded as piracy (e.g., here, para. 19; here, p. 99; here, p. 40-41).
While UNCLOS may not be the right framework to deal with such issues, this post suggests that it may be indirectly relevant as in practice certain violations of UNCLOS, mainly the freedom of navigation, may invoke the right of self-defence, beyond the formal legal regime.
Challenges to the applicability of the right of self-defence
The situation in the Gulf of Aden raises questions concerning the application of self-defence. Invoking self-defence is subject to certain conditions, which may be difficult to satisfy in the context of the Houthis’ attacks. First, an attack against a state must be imminent. Self-defence is not reserved only for attacks that have already occurred, but ‘anticipatory self-defence’, where the threat is not imminent, has not been accepted (e.g., Shaw, p. 1000). The Houthis’ attacks justify self-defence in cases where a vessel is already in a position to defend itself and an attack is about to begin. However, sending military forces to deal with foreseeable but not imminent threats likely fails to meet this condition.
Second, a state must demonstrate that it is the victim of an armed attack. The ICJ determined that an attack on vessels that are owned but not flagged by a state may not be an armed attack against that state. Thus, an attack on a US-owned cargo ship, registered under a different flag, might not trigger the right of self-defence for the US. In addition, attacks from a distance may also fail to prove the intention to attack a specific ship, which is required to exercise self-defence (Shaw, p. 995). Thus, in cases of attack from the shore by missiles, the targeting of a specific state may not be inferred.
Arguably, collective self-defence may be relevant in this situation. However, as the requirements of the right of self-defence must be fulfilled and the attacked state must request assistance (Dinstein, p. 315), there is a question regarding the application of this framework. First, the analysis above raises some doubts regarding the conditions for self-defence. Second, there is no indication that any relevant state, such as the US, has requested assistance. At least some attacks by the Houthis may not justify invoking collective self-defence.
Furthermore, in the current situation, states do not use the language of self-defence. Instead, they argue for the protection of the freedom of navigation and international commerce. The ICJ recognized the link between freedom of navigation and the use of force, but only in maritime zones under national jurisdiction (Nicaragua, paras. 210-214). Thus, violating the freedom of navigation on the high seas might not trigger the right of self-defence. In addition, coercive economic actions alone are generally outside this legal framework (Shaw, p. 988).
However, a strictly legal approach as analyzed above may lead to absurd results, as it would prevent states from dealing with such attacks or threats to international waterways and peace and security. Reviewing the current practice may suggest an informal broadening of the scope of self-defence, which would provide an alternative framework to deal with such issues.
Current practice
States argue that protecting freedom of navigation and global commerce is a justification to employ military force in the absence of a binding United Nations Security Council (‘UNSC’) authorization under Chapter VII. State practice and practice of international organizations such as the latest UNSC Resolution concerning the Houthis’ attacks may suggest that these rationales could justify invoking self-defence. This would be a departure from the legal framework of self-defence outlined above. Recent practice also implies a change in the scope or interpretation of the conditions of self-defence.
With respect to the practice of international organizations, in contrast to the ICJ’s interpretation regarding the freedom of navigation and the use of force, the UNSC implied that impeding navigational rights on the high seas can constitute an attack. Although this is not a binding decision under Chapter VII, it may still reflect an accepted position of the international community.
In fact, this resolution is in line with the statements of other international organizations. The Secretary-General (‘SG’) of the International Maritime Organization (‘IMO’) indicated that all states must ensure the freedom of navigation, even if their vessels were not victims of an attack (e.g., here, here). NATO’s SG iterated this position. This is not the first time NATO has referred to the freedom of navigation as a justification for using force. Last, the member states of the European Union (‘EU’) approved a new mission to protect international shipping in the Red Sea. EU diplomats specifically mention the ‘priority of free navigation’ as part of the rationale for this initiative.
Current state practice also implies that threats to the freedom of navigation and global commerce may justify exercising the right of self-defence, thus broadening the scope of the legal regime. For example, the US and UK specifically mentioned freedom of navigation as justification for the strikes against the Houthis in Yemen in January 2024 (here, here). This is supported by the US-led coalition’s statement.
These positions broaden the interpretation of the term ‘attack’ and the designated target of such attack beyond the current legal framework. The international community’s lack of response may be read as an acceptance of this broadening (e.g., here, p. 139, para. 5). Except for Iran, Turkey, and Russia, there is no international response that condemns military action against the Houthis.
The argument regarding the broadening of the legal framework of self-defence finds support also in past instances, where states have been willing to use force to preserve freedom of navigation and global commerce. For example, in 2018 an Arab coalition operating in the Red Sea and the Gulf of Aden explicitly expressed these goals. Although there was a binding UNSC decision concerning the situation, it did not authorize the use of force. Thus, the military response was outside the formal legal regime. Still, states seem to continue accepting the new rationale to invoke self-defence. This is supported by individual state practice. For example, the positions of Saudi Arabia, the US, and Iran concerning the ‘tanker-war’ in the Gulf of Oman area in 2019 reflect the above rationale (e.g., here, here). All states essentially maintained the ability to use force to preserve economic interests.
UNCLOS and the right of self-defence
The analysis above highlights that violation of certain provisions of UNCLOS may justify self-defence, thus broadening both UNCLOS and the legal framework of self-defence. The freedom of navigation is entrenched in UNCLOS and other relevant instruments (UNCLOS, Art. 38, 58, 87, 125; High Seas Convention, Art. 2-3). The principle of freedom of navigation is closely linked to global commerce (e.g., here, para. 17; here, paras. 26-27). Thus, the language of states, coalitions and international organizations essentially implies that breaching these provisions of UNCLOS may justify invoking the right of self-defence.
It is noteworthy that, in the current situation, the violations were committed by the Houthis (an entity that cannot be a party to UNCLOS) and allegedly Iran, which is also not a party. Thus, ostensibly they cannot breach the Convention. However, the freedom of the High Seas is a rule of customary international law, which is binding at least on Iran. Even if the actor that carries out the threats does not legally breach UNCLOS, the act itself is as good as a breach of UNCLOS. In practice, states legitimize military responses against actors that are not necessarily obligated to respect the freedom of navigation, similar to exercising self-defence against non-state actors.
Concluding remarks
While the situation in the Gulf of Aden violates the freedom of navigation, UNCLOS is not the appropriate governing framework. Furthermore, there are some doubts regarding the applicability of self-defence as some of the conditions are not met. However, in practice, states perceived threats to the freedom of navigation and global commerce, which are essentially a breach of UNCLOS, as justification for self-defence, thus broadening the scope of the formal legal regime.
This is similar to humanitarian intervention or the ‘responsibility to protect’ (R2P). while these concepts have no sound legal basis, they justify the use of force from a moral perspective. The difference between these concepts and the response to the Houthis is that humanitarian intervention and R2P are supposedly new frameworks alongside the formal legal regime of self-defence. In contrast, current state practice seems to be within the formal legal framework, broadening and changing it.
Dr. Shani Friedman is a lawyer and a postdoctoral researcher in international law at UBO, AMURE lab, Brest, France. She has a PhD from the Law Faculty of the Hebrew University of Jerusalem. Her fields of expertise are international relations, and international law, specifically the law of the sea and international institutions. She can be found on Twitter, LinkedIn, and AMURE.