The International Law Commission's 2019 Draft Conclusions on Peremptory Norms of International Law assert that States have an obligation to cooperate to end serious breaches of peremptory norms. International law provides scarce guidance, however, regarding how States are expected to fulfil that obligation. This article seeks to elaborate: first, whether the prohibition of crimes against humanity and the ‘basic rules’ of international humanitarian law are peremptory norms; second, what States are required to do to fulfil their obligation to cooperate; and third, how States might utilise the General Assembly as a forum through which to fulfil that obligation.

This article argues that if there is a jus cogens norm in the jus ad bellum, it must be the customary norm which prohibits non-consensual uses of force that are neither validly authorised under the UN Charter nor lawful exercises of self-defence. In doing so this article will clarify the method by which jus cogens norms should be identified, based on a correct understanding and application of what it means for a norm to be ‘accepted and recognized as a norm from which no derogation is permitted’. It is argued that all existing jus cogens norms must be norms of customary law, and that the uncertainty regarding the scope of the jus cogens norm prohibiting force results from uncertainty as to the structure of the underlying customary and treaty law norms in the jus ad bellum.

International law has not traditionally recognised individuals as victims of the crime of aggression. Recent developments may precipitate a departure from this approach. The activation of the jurisdiction of the International Criminal Court over the crime of aggression opens the way for the future application of the Court's regime of victim participation and reparation in the context of prosecutions for this crime. The determination by the United Nations Human Rights Committee in General Comment No. 36 that any deprivation of life resulting from an act of aggression violates Article 6 of the International Covenant on Civil and Political Rights serves to recognise a previously overlooked class of victims. This article explores these recent developments, by discussing their background, meaning and implications for international law and the rights of victims.

The Syrian civil war has highlighted the phenomenon of foreign fighting, in which individuals leave their home State to join an armed conflict overseas. The predominant paradigm for regulating foreign fighting, centred on United Nations Security Council Resolution 2178, is based on counterterrorism, which in essence treats foreign fighting as a form of terrorism. This paradigm is largely reflective of the domestic legislation of the United Kingdom, United States, Canada and Australia. This article argues that this approach is problematic, and that an alternative paradigm based on the international law of neutrality and related domestic legislation provides a better means for regulating foreign fighting.

The proliferation of legal and normative standards regulating women's rights in conflict has been accompanied by concerns about their efficacy. The article examines the activities of the CEDAW Committee and the UN Security Council and considers how synergies might be advanced. The article finds that, while the Security Council has unique authority over UN system activities, sanctions and peacekeeping, the CEDAW Committee—as a human rights treaty monitoring body—possesses the more effective system of State accountability and the more robust commitment to women's equality and rights. The article proposes measures for the optimum interaction between both institutions in order to maximize overall accountability for women's rights in conflict.

A ‘safe zone’ refers to an area established in armed conflict for the purposes of protecting civilians. This article provides the first legal analysis of whether safe zones can be invoked as a ground for refusing asylum. It examines the concept of the Internal Protection Alternative (IPA) which posits that an individual is not a refugee if there is a safe place within his/her country where he/she can relocate. It clarifies the applicable criteria in the IPA inquiry and uses three case studies to illustrate that safe zones can only qualify as lawful IPAs in exceptional circumstances.

This article seeks to make sense of two seemingly contradictory aspects of the General Assembly's practice: its history of recommending to States that they impose unilateral sanctions; and its series of resolutions denouncing unilateral coercive measures as illegal. It examines the seeming discrepancy between the customary international law position regarding unilateral sanctions, and the position asserted by the Assembly, and argues that on a nuanced reading of the Assembly's resolutions, these positions are not so divergent as is often supposed. The article concludes by examining the scope for the Assembly to make future sanctions recommendations, consistently with its prior condemnation of unilateral coercive measures.

Article 16 of the International Law Commission's Articles on State Responsibility provides that a State that aids or assists another State in the commission of an internationally wrongful act by the recipient State is internationally responsible, where certain conditions are fulfilled. This article clarifies one of those conditions, namely the difficult and contested issue of what degree of knowledge or intent engages the responsibility of an assisting State under Article 16. The article focuses particularly on assistance in armed conflict and counterterrorism situations, which increasingly feature some form of operational or intelligence cooperation between States.

This article considers the positive evolution of international law in the past century, and the emergence of a rules-based multilateral system under the UN Charter, which has, inter alia, enabled formerly colonised peoples to exercise their right to self-determination and prohibited the use of force in international relations. The author reaffirms his faith in the ability of international law to provide a common language for the international community to face successfully common challenges, such as poverty, global warming, and the protection of privacy rights in the era of social media and artificial intelligence. Looking beyond traditional beneficiaries and duty-bearers of international obligations, the author makes a case for all actors to engage in respecting, upholding and promoting international law.

This article examines the applicability of the European Convention for Human Rights (ECHR) when a State loses control over parts of its territory. It argues that the jurisprudence of the European Court for Human Rights, which insists on residual positive obligations based in sovereign title over territory, is problematic and needs to be rethought. The Court's current approach is not only likely to provoke backlash, since it requires it to decide politically explosive questions of sovereign title, but does so for very little practical benefit for the protection of human rights. The article therefore explores more preferable alternatives.

This article explores the phenomenon of ‘disaggregation’ of disputes in international law, that is, the carving up of broader disputes into discrete legal claims based on different international legal rules and subject to the jurisdiction of different international tribunals. In particular, its focus is on certain under-explored consequences of this phenomenon for the jurisdiction of international tribunals, asking whether the relationship between the specific claims and the broader dispute might affect the jurisdiction of the tribunals. Employing the ongoing Ukraine/Russia dispute, which has yielded multiple claims before different international tribunals, the article offers an original analysis of these jurisdictional questions. It presents three approaches discernible from case law where tribunals face claims over which they appear to have jurisdiction that implicate a broader dispute over which they do not. The article ends with a consideration of possible explanations for why a tribunal might follow one approach over the others in any given case.

Humanitarian actors sometimes have to decide whether to render assistance in situations that put them at risk of liability for aiding and abetting under international criminal law. This is the problem of the virtuous accomplice—the idea that knowingly contributing to the wrongdoing of others might, exceptionally, be the right thing to do. This article explains why the problem arises and clarifies its scope, before turning to criminal law in England and Wales and Germany to assess potential solutions. It argues that the best approach is to accept a defence of necessity—of justified complicity—and shows that such an argument works in international criminal law.

The definition of the crime of aggression in Article 8 bis of the Rome Statute of the International Criminal Court (Rome Statute) stipulates that a State act of aggression is a material element of the crime, suggesting an intrinsic link between individual criminal responsibility and State responsibility for aggression. This article argues that the Rome Statute provides a legal basis for the International Criminal Court (ICC) to determine State responsibility for aggression when considering the material elements of the crime of aggression, which has important practical and conceptual implications for the law of international responsibility. Although the content of State responsibility flows automatically from the breach of the obligation, it is argued that a finding of aggression pursuant to Article 8 bis of the Rome Statute may be considered as a form of satisfaction for the purposes of Article 37 of the 2001 ILC Articles on Responsibility of States for Internationally Wrongful Acts (2001 ILC Articles). Furthermore, the material element of the crime in Article 8 bis of the Rome Statute requires the act of aggression by its character, gravity, and scale to constitute a manifest violation of the Charter of the United Nations, in line with the nomenclature used within the 2001 ILC Articles regarding serious breaches of obligations arising from peremptory norms of general international law (jus cogens). The article considers the important role that the ICC may play in relation to serious breaches of the jus cogens obligation to refrain from an act of aggression.

In its 2015 judgment in the Costa Rica v Nicaragua case, the International Court of Justice (ICJ) found that Nicaragua's establishment of a military presence in disputed territory violated the territorial sovereignty of Costa Rica. Two judges considered that Nicaragua's actions had constituted a breach of Article 2(4) of the United Nations (UN) Charter, but the majority of the judges chose not to pronounce on the issue. Whilst it has been clarified that the prohibition of the use of force applies to a disputed territory, it seems less clear as to whether such force has to be violent in nature, causing injury to human beings or damage to property, for it to be in breach of Article 2(4). The ICJ's Advisory Opinion on the Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory case strongly indicated that the construction of the wall breached Article 2(4). If a State establishes a military presence to change the status quo in a disputed territory, it would not be regarded as a ‘peaceful’ means of settling the territorial dispute. Therefore, such behaviour would violate Article 2(3), under which States shall settle their international disputes ‘exclusively’ by peaceful means. Furthermore, to constitute an unlawful use of force under Article 2(4), the establishment of a military presence in a disputed territory does not have to be violent but should involve coercion that makes it materially impossible for other claimants to restore the status quo ante without risking human injury or damage to property.