The restriction of personal liberty is a critical feature in all conflicts, whether they are of an international character or not. With the increased prevalence of non-international armed conflict and the drastic proliferation of non-state armed groups, it is critical to explore whether such groups can legally detain or intern persons during conflict. This article proposes that there exists a power and a legal basis for armed groups to intern persons for imperative security reasons while engaged in armed conflict. It is suggested that this authorisation exists in the frameworks of both international humanitarian law and international human rights law, as it does for states engaged in such conflicts. It is proposed that such power and legal basis are particularly strong for armed groups in control of territory, and can be gleaned from certain customary law claims, treaty law, as well as some case law on international humanitarian law and human rights. Certain case law of the European Court of Human Rights on detention by de facto non-state entities conceivably reflects a change in traditional thinking on ‘legal’ detention by armed groups.

The realities of contemporary armed conflicts with a complex interweaving net of actors are rarely reminiscent of classic combat scenarios envisaged by the drafters of the Geneva Conventions. The scarcity of conventional regulation of non-international armed conflicts (NIACs), coupled with the non-state character of the majority of detaining powers, lead to lack of clarity regarding the legal regime of detention of persons captured by non-state armed groups (NSAGs). In the absence of an explicit authorisation for internment under the international humanitarian law applicable to NIACs, recent developments in case law have induced a scholarly debate on what is the legal basis for administrative detention carried out by these actors. The article analyses key arguments presented by both sides of the debate, concluding that neither side can demonstrate either the existence or the absence of the authorisation in question, while the discussion itself has limited practical value in regulating the conduct of NSAGs. At the same time, the practice of states, although still ambivalent, points to the gradual transformation of mere legality, or the so-called ‘inherent power’ to intern, into a customary provision providing a legal basis for administrative detention by NSAGs.

The participation of foreign fighters on the side of terrorist groups has raised many questions about the legal basis for the criminal prosecution of acts of terror during armed conflicts. In cases regarding the commission of terrorist crimes with transnational elements, such as the foreign nationality of the alleged perpetrator, cooperation with other states in matters such as extradition or mutual legal assistance can be crucial. This study will analyse two regimes that may constitute a legal basis for cooperation in criminal matters against acts of terror committed during armed conflicts: (i) the rules on criminal responsibility under international humanitarian law (IHL), and (ii) the United Nations framework of anti-terrorist conventions. IHL has been seen by many as the only framework applicable to acts committed during armed conflicts. In contrast, the position adopted in this article is that IHL does not necessarily exclude the application of other regimes to acts committed during armed conflicts, which can serve as a complementary tool in international efforts for the prevention and suppression of terrorism.

The article seeks to shed light on a lacuna in the law and international adjudication regarding the entitlement of coastal states to the exclusive economic zone (EEZ), by analysing the implicit requirement in the UN Convention on the Law of the Sea of proclamation to establish such entitlement. The main argument of the article is that despite the requirement for proclamation, there is no definition of this act in international law that clarifies its legal status. Nonetheless, failure to heed the requirement to proclaim an EEZ can affect the establishment of the EEZ, which in turn affects the rights and jurisdictions of coastal states in the zone. It can also affect the competence of judicial institutions to decide on matters such as delimitation of overlapping zones.

Ever since the Wednesbury decision in 1947, United Kingdom public law has been applying the concepts of ‘rationality’ and ‘reasonableness’ indistinguishably. Rationality has also been used as a ‘mega-ground of judicial review’, covering many other, distinct grounds of review. The main purpose of this article is to promote conceptual clarity in UK public law by highlighting the overlooked differences between reasonableness and rationality, indicating the nature of rationality as a distinct ground of judicial review and explaining why it should not be used as a mega-ground of review. It is argued that (i) reasonableness is in its essence a balancing and weighing test; (ii) the most accurate way of understanding rationality review in public law is to perceive it as ‘instrumental rationality’ or as a ‘suitability test’ which reviews the logical and causal connection between means and end; (iii) this ‘instrumental’ perception of rationality is already applied in UK public law as part of the proportionality test; (iv) rationality, unlike reasonableness, is not a weighing and balancing test; thus it is wrong to use the concepts of ‘reasonableness review’ and ‘rationality review’ indistinguishably; and (v) it is conceptually wrong and confusing to use rationality as a ‘mega-ground of review’.

The conventional historic account maintains that international criminal law (ICL) was ‘born’ after the Second World War. This account is incomplete, as William Schabas's book, The Trial of the Kaiser (2018), captivatingly shows by richly portraying the (aborted) First World War initiative to try the German Kaiser before an international tribunal. However, this article (after providing an overview of Schabas's book) argues that Schabas's account of a First World War ICL ‘birth’ is also incomplete. ICL during the First World War era was but one link in a much longer historical chain. The essay demonstrates this fact by presenting certain elements of the long (forgotten) history of ICL, which provide answers to questions that have been left unanswered, not only by the conventional account (of a Second World War ICL ‘birth’) but also by Schabas's account (of a First World War ICL ‘birth’). As the article discusses, the unveiling of a greater ICL history indicates that international criminal tribunals are not a modern innovation, and reveals the origins of ‘crimes against humanity’, of ‘aggression’ and of the universal jurisdiction doctrine. The essay further discusses reasons for the non-remembrance of the long history of ICL, the importance of acknowledging that history, and the likelihood of it becoming widely acknowledged in the near future.