Nulla poena sine lege is a Latin phrase that means “no penalty without law.” This legal concept, which has long been a fundamental idea of written law, forbids the penalization of actions that are not governed by a statute or law. Nulla poena sine lege, though it seems rather straightforward, sometimes causes controversy in the matter of jurisdiction.
The concept of nulla poena sine lege is closely related to several similar concepts. Usually, it works in conjunction with the idea that there is no crime without a law, or nulla crimen sine lege, to protect people from being convicted and punished when there are no laws against their actions. It is also frequently mentioned alongside another Latin phrase, nulla poena sine praevia lege poenali, which means that a new law cannot be used retroactively to punish people.
This last term is quite important to the practice of nulla poena sine lege, as it can prevent legal systems from creating laws to punish past behavior. If, for instance, a city noticed a pattern of graffiti tagging, but had no law against it, nulla poena sine lege would suggest that taggers could not be punished until after a law is made that makes the action an offense. What nulla poena sine praevia lege poenali guarantees, in this instance, is that no person could be tried or convicted for tagging before the law came into effect. Since the action was not illegal at the time, it is generally considered a miscarriage of justice to assign penalties following a new criminal statute.
Nulla poena sine lege comes into some contention on the matter of international law and jurisdiction. The Nuremberg Trials are frequently mentioned as a primary source of controversy on this matter, since many of the crimes Nazi leaders were charged with did not exist in law until after World War II. Moreover, since the actions of the Nazis were expressly in order with German law, some critics question whether the international tribunal had any right to supersede the sovereignty of Germany. Since the crime of genocide did not truly exist, nor had any statuary penalties been assigned to such a crime, a strict interpretation of nulla poena sine lege might suggest the Nuremberg trials were unlawful.
One of the most important effects of nulla poena sine lege is that it places a check on judicial power. By limiting punishments to those proscribed by statutes, the potential to assign extreme punishments is held at bay to some degree. Judicial activists sometimes argue that these strictures are too rigorous and may prevent judges from fairly considering each case on an individual basis. Nevertheless, nulla poena sine lege remains an influential and critical part of many legal systems in the modern world.
