Chad's former head of state, Hissène Habré, who has died at the age of 79, was serving a life sentence in Senegal following his conviction for war crimes, crimes against humanity and torture.
Habré was tried by a specially constituted tribunal set up by an agreement between the African Union, Senegal and Chad. Staffed mostly by local judicial professionals, it investigated crimes committed in Chad from 1982 to 1990 while Habré was in power. Tribunal investigators travelled to Chad four times and collected thousands of interviews which informed Habré's prosecution and 2016 conviction.
The tribunal was unprecedented. It represented Africa's first locally produced international criminal law, its first application of universal jurisdiction, and its first judicial challenge to a former dictator's quiet retirement.
Habré's trial and conviction were significant and legally innovative in many ways. And his trial and conviction was great news for international criminal law, in part because it was some of the only good news for the field in the past decade.
But as I argue in my forthcoming book, the trial should be seen as a failure to the degree that it was only able to neutralise Hissène Habré, the man, and not the criminal state governance practices he oversaw. The repressive state apparatus and practices Habré built up remain in place today.
The field of international criminal law emerged after the second world war, when allied powers put defeated German and Japanese leaders on trial in Nuremberg and Tokyo. International criminal law allows individuals to be criminally charged for their roles in state-sponsored atrocity. The words "crimes against humanity" and later "genocide" entered the lexicon of the law for the first time.
Whereas international human rights law instructs states to change their practices, international criminal law investigates and prosecutes specific individuals for their roles in committing crimes against humanity, war crimes, or genocide.
After the legal innovations of the Nuremberg and Tokyo trials, international criminal courts lay dormant until the end of the Cold War. In the 1990s, violence in the former Yugoslavia and Rwanda led to UN-sponsored tribunals in The Hague and Arusha. In 1998, countries around the world negotiated the Rome Statute, leading to the founding in 2002 of the International Criminal Court, the first permanent court applying international criminal law.
The International Criminal Court currently has 123 member states. It has held several trials and has five convictions for atrocity crimes. In 2015, it moved into its permanent headquarters, a grand building complex in The Hague. A plaque in the entrance reads, "Towards a more just world".
Despite these considerable achievements, the court faces numerous existential challenges. It's focus on African conflicts and African defendants has led to resistance. The African Union has on numerous occasions instructed African states to withdraw from it.
The court has also struggled to elicit cooperation from member states, rendering investigation impossible. Moreover, some of the world's most powerful states, including India and three of the five permanent members of the UN Security Council - Russia, China and the US - are not members and often oppose the court.
In this charged landscape, Habré's trial and conviction was a boon both to the field of international law as well as to the beleaguered International Criminal Court.
Although the special court constructed to try Habré for atrocities committed in Chad from 1982 - 1990 might look like a competitor to the International Criminal Court, the Habré tribunal is better understood as an ally.
First, Habré's case could never have been taken on by the International Criminal Court, which can only hear cases involving crimes that have occurred after its founding in 2002.
Second, Habré's trial conformed to both the principles and the particulars of international criminal law. The International Criminal Court is a court of last resort, designed to intervene only when local courts cannot or will not. Therefore, local prosecution of crimes recognised by the International Criminal Court fulfils the the court's mandate. Moreover, since international criminal law challenges the idea that might makes right, challenging sovereign immunity and impunity is one of the International Criminal Court's aims.
Finally, Senegal's tidy administration of the case set an example for how local institutions can perform international criminal law adjudications. The trial was completed on time, with a minimal budget, and unmarred by witnesses casualties or bureaucratic corruption.
Thus even though there was a lot of focus on the Habré trial as an "African institution" often in order to distinguish it from the unpopular "western" International Criminal Court, the Habré tribunal was good news for the International Criminal Court and its international criminal law project.
The legacy of Habré's trial and conviction is more mixed when we consider what it means for Chad. As discussed in my co-edited book about the trial, the case against Habré was in many important respects driven by his victims, and his conviction represented an official recognition that the harms they suffered were crimes.
This paradigm shift between unfortunate harm and punishable - and therein preventable - crime is a central aspect of the value that international criminal law promises.
On the other hand, Habré's conviction arguably represents a somewhat empty gesture against low-hanging fruit. For example, while wrongs towards victims are recognised by the verdict, the reparations that the court ordered have not been collected or dispersed.
Courts in Chad have also ordered reparations, to no avail.
Moreover, the repressive state apparatus Habré oversaw was continued by his successor, Idriss Déby. Déby was a major funder and supporter of the legal case against Habré up to the point where the tribunal began investigating crimes where he was involved. At this point his cooperation abruptly ended.
Déby ruled Chad despotically for more than 30 years until his unexpected death in a military skirmish earlier this year. He has been replaced by his son, Mahamat Idriss Déby, who has so far overseen regime abuses reminiscent of those committed by Habré.
The value of the rule of law is to challenge and constrain power. In this sense, the legacy of Habré's trial and conviction is mixed.