Research Associate Eduardo Cavalcanti de Mello Filho has published the article titled ‘Operations for the protection of foreign-flagged vessels at sea against Houthi attacks: a case of collective self-defence?’ in the Journal on the Use of Force and International Law.

Eduardo examines the legality of EUNAVFOR’s Operation Aspides and of the US-led Operation Prosperity Guardian for the protection of ships in the Red Sea. Building on a previous article in which he argued that individual Houthi attacks against merchant vessels may amount to ‘armed attacks’ triggering the right of self-defence, he contends that both operations constitute collective self-defence.

He argues, in particular, that a formal request from the victim flag State is not required in the context of protecting ships at sea. The International Court of Justice’s requirement for such a request was derived from a specific factual and legal context that does not apply in this context. Moreover, he finds that consistent State practice suggests that such requests have not been considered necessary. Indeed, most maritime administrations have encouraged their vessels to rely on foreign naval protection.

The paper is available at https://www.tandfonline.com/doi/full/10.1080/20531702.2025.2522522