Legality Matters

Retroactive criminal laws are a challenge to the fairness and legitimacy of criminal justice systems. The danger of these laws has resulted, in international law, in an absolute prohibition on their use. Using the crimes against humanity prohibition on other inhumane acts, I suggest that we need to rethink our understanding of retroactive criminal law and its absolute prohibition. Retroactive law exists on a spectrum with vague laws; we need to consider at what point a law becomes so ill-defined that its clarification ceases to be an issue of interpretation and requires an act of law-making. We then need to ask in which circumstances the application of retroactive criminal laws are fair. This places a particular burden on courts and tribunals: they are responsible for creating new law and determining whether its application in a specific case will enhance or undermine the legitimacy of their legal system. In this work, I use the crimes against humanity prohibition on other inhumane acts to explore this issue. This chapter provides an overview of the argument contained in this book.

In this chapter I focus on the prohibition on the use of retroactive criminal law. This is done largely through an exploration of the work of Lon Fuller. I examine Fuller’s preoccupation with the law-making process and what he referred to as the morality that makes law possible. Fuller articulated eight desiderata of legality: elements essential to law-making. According to Fuller, law-making does not require the perfect application of these desiderata in every instance. Fuller described the task of law-making as finding the correct balance of the desiderata to maintain the legitimacy of the legal system. Among his desiderata was the prohibition on retroactive laws. While Fuller generally condemned the use of retroactive laws, he identified the prohibition as being among the desiderata which require balancing. In doing so, Fuller left open the possibility that retroactive laws may be acceptable in limited circumstances. However Fuller articulated a strong rejection of the use of retroactive criminal laws. I argue that a consideration of his work suggests this rejection was not absolute. Fuller’s work can help to explain both when retroactive criminal laws may be acceptable and how their use can enhance rather than undermine the legitimacy of a legal system.

The development of crimes against humanity has been comprehensively traced in many works. In this chapter, I consider that development and argue that crimes against humanity were retroactive at their first application in 1945 and remained retroactive until the 1990s. I rely on my argument that to overcome the prohibition on retroactive criminal law, a crime must be defined. International crimes are distinguished by their contextual elements. Until the work of the ad hoc tribunals and negotiators of the Rome Statute in the 1990s, the contextual elements of crimes against humanity remained uncertain. The crimes were not defined. I go on to argue that in spite of the retroactive nature of crimes against humanity, their use in prosecutions throughout the latter half of the twentieth century was legitimate. I draw on the work of Lon Fuller to argue that while crimes against humanity were retroactive laws, they were not an objectionable form of retroactive law. In the last section of this chapter, I argue that careful consideration of what makes laws retroactive and when such laws may be justifiably deployed remains a key concern because crimes against humanity are deliberately open-ended. The law was always intended to be applied to new, unspecified, atrocities. To ensure the law remains legitimate, we need to be attentive to the justifiable limits of retroactive criminal law.

It was always intended that the law of crimes against humanity would continue to evolve in order to effectively respond to atrocity crimes. The mechanism through which crimes against humanity are able to evolve is the prohibition on other inhumane acts. This provision permits authorities to charge an accused for acts which are not specifically prohibited. In this chapter, I analyse the way in which the ad hoc tribunals and ICC have interpreted the prohibition on other inhumane acts. I argue both that the methodologies used were flawed and that the resulting interpretation is highly problematic. The current approach to the prohibition on other inhumane acts can neither account for some existing results nor offer certainty in future trials. I argue that the fundamental difficulty is that the prohibition on other inhumane acts has been misconceived. It is not a substantive prohibition which simply requires interpretation; it is a direction to courts and tribunals to act as law-maker and an invitation to create and apply new criminal laws. This approach would ensure more careful attention to the concerns underlying the prohibition on retroactive criminal law: notice, restraint of arbitrary power and legitimacy. The current approach to the prohibition on other inhumane acts risks undermining the legitimacy of the law. A new approach is needed.

The existing approach to the crimes against humanity prohibition on other inhumane acts is deeply flawed. In my last chapter, I suggested that a new approach to the prohibition was required: one based on the understanding that the prohibition is a direction to courts to act as law-makers and an invitation to courts to create and apply retroactive criminal laws. In this chapter, I elaborate on that new approach. The starting point is to identify how unlisted acts are like the listed prohibitions in the various articulations of crimes against humanity. To understand whether an unlisted act is “like” one of the existing prohibitions, we need to understand what the term “inhumane” means. I propose a victim-focussed understanding drawn from domestic criminal law theory. Using the work of Stephen Shute and John Gardner, I argue that for the purpose of the prohibition on other inhumane acts, inhumanity must be understood as sheer use of a person. Building on this, I articulate a new analytical approach to recognizing and defining new, permanent, other inhumane acts. I deploy the theory of Lon Fuller to show how this new approach would, unlike the current approach, reinforce the legitimacy of the law.