On May 21, 2020, a Tribunal established under Annex VII of the United Nations Convention on the Law of the Sea (UNCLOS) rendered an Award regarding the 2012 Enrica Lexie incident, which involved the death of two Indian fishermen at the hands of Italian Marines. The Award is lengthy and wide-ranging, finding that: (1) Italy and India had concurrent jurisdiction over the incident; (2) the Tribunal had incidental jurisdiction to determine the immunity of the Italian Marines; (3) the Marines enjoyed immunity as state officials; but nevertheless that (4) India was entitled to compensation for the loss of life, physical harm, damage to property, and moral harm. The Award has been received more positively by Italy than India, but neither party has indicated that they intend to do anything other than comply with it.

By a September 17, 2019 Order (Order), the German Federal Constitutional Court (FCC or Court) rejected challenges to Germany's military involvement in anti-Islamic State of Iraq and Syria (ISIS) operations in Syria. This outcome was expected and was as such insignificant. What is significant is the FCC's reasoning. The Court used the Order to clarify the constitutional roles of parliament and the executive in German foreign affairs. And it included an intriguing pronouncement on the scope of Article 51 of the UN Charter, which adds a fresh perspective to the polarized debates about self-defense against nonstate actors.

In the grand debates of international law, the jus ad bellum is often proclaimed dead, and just as often praised as the “cornerstone” of the contemporary legal order. Both perspectives tend to ignore that the jus ad bellum is not static, but a body of law that states adjust over time. In an important contribution, Monica Hakimi proposes to look at one particular aspect of such adjustment, a concept she frames as “informal regulation” through Security Council action. This essay engages with Hakimi's approach. It inquires whether this approach is as “informal” as Hakimi suggests, and asks whether “informal regulation”—rather than constituting a new category of state activities to study—is not already part of conventional approaches to the jus ad bellum. Proceeding from Hakimi's analysis, the comment assesses whether there is room for “informal regulation” beyond the Security Council.

This introductory paper to the symposium hosted by the Leiden Journal of International Law, and edited by the authors, deals with the function of domestic courts as agents for the development of international law. The paper ‘sets the scene’ for the contributions to the symposium, which seek to trace the impact of domestic courts in the development of canonical areas of international law, such as jurisdiction, immunity, state responsibility, the law of international organizations/human rights, and the law of armed conflict/conduct of hostilities. It discusses the formal quality and actual influence of domestic-court decisions on the development of international-law, and introduces the concept of ‘agents’ of international-law development. This is the analytical perspective that the contributions to the symposium adopt.

Recent years have seen increasing reliance on self-defence as a concept justifying the use of force against armed attacks by terrorists operating from within a foreign state. While the matter has prompted major debates, a good case can be made that contemporary international law now begins to recognise a right of self-defence against attacks by terrorists. (We will refer to this in the following as ‘anti-terrorist self-defence’, meaning a response directed against an attack carried out by a terrorist organisation.) This article deliberately does not rehearse the major debates about the scope of self-defence, but moves beyond them. It seeks to assess whether and how the two main limitations on the exercise of self-defence – namely necessity and proportionality – could be adapted to self-defence outside the inter-state setting. It shows that both limitations do indeed require some adaptation in order to be applied to anti-terrorist self-defence.

With respect to necessity, we argue that this adaptation is actually a chance to make sense of a requirement that is of very limited practical relevance in the inter-state setting. As the article shows, necessity can assume a crucial role in the anti-terrorist setting: in order for trans-border uses of force to be necessary, states invoking self-defence must demonstrate that the terrorist threat cannot be repelled by the host state (on whose territory the terrorists are based).

As for proportionality, recent debates about anti-terrorist self-defence expose the weaknesses of proportionality as a restraint on self-defence. Construed primarily as a prohibition against excessive force, even in the inter-state setting, proportionality has always been dependent on the nature of the aims pursued in the name of self-defence. Recent anti-terrorist practice suggests that many states are prepared to accept far-reaching uses of force against terrorists. It also suggests that, in applying proportionality, the targeted (or otherwise) character of the response is of crucial importance. The law is clearly in a state of flux, but in debates such as those about Turkey's use of force against the PKK or Israel's military operations against Hamas or Hezbollah, one can see the beginning of a process of developing guidelines on proportionality.