Perverse effects of the nulla poena principle: national practice and the ad hoc tribunals

The prohibition of retroactive punishments, known by the Latin expression nulla poenas sine lege, is a component of the principle of legality. Out of the concerns with retroactive sentencing and to enhance the fundamental rights of the accused, the statutes of the ad hoc tribunals for Rwanda and the Former Yugoslavia require judges to establish prison terms in the light of national practice in the place where the crimes took place. These provisions have proven difficult to apply. It is unclear whether reference should be made to the prison terms set out in penal statutes or to the actual practice of local courts, and at what point in time. Furthermore, because both Yugoslav and Rwandan law have provided for capital punishment, attempts to draw parallels are necessarily distorted. As a result, judges at the Yugoslav Tribunal have found the provisions to be of marginal relevance. Judges at the Rwanda Tribunal have applied the provision in support of harsh sentencing, suggesting that those convicted are being treated favourably compared with those judged by Rwandan courts, where sentencing options include the death penalty. Thus, a legal provision intended to protect the accused from abusive punishment has been twisted into an additional argument in favour of severity.