Principle of legality in criminal law

The principle of legality in criminal law was developed in the eighteenth century by the Italian criminal lawyer Cesare Beccaria and holds that no one can be convicted of a crime without a previously published legal text which clearly describes the crime (nulla poena sine lege). This principle is accepted and codified in modern democratic states as a basic requirement of the rule of law. It has been described as "one of the most 'widely held value-judgement[s] in the entire history of human thought' ".

Brazil
In Brazil, the Principle of legality (Princípio da legalidade) is enshrined in the Constitution in Article 5, paragraph 2, which states that "No one shall be compelled to do or refrain from doing anything except by law".

Canada
In Canada, the principle of legality in penal law is found in Article 9 of the Canadian Criminal Code which declares that criminal infractions must fall under Canadian law, and that no one may be found guilty of a criminal infraction under common law. The principle of legality is also mentioned in Article 11g: "Every defendant has a right to not be found guilty of an action or omission which, at the moment it took place, did not constitute an infraction under the internal law of Canada..." Article 11g does however make an exception for crimes unanimously considered in international law to be genocide or crimes against humanity.

Council of Europe
Member states of the Council of Europe (all internationally recognized countries in Europe except Belarus, Russia, and Vatican City, plus Armenia, Azerbaijan, Cyprus, and Georgia) are parties to Article 7 of the European Convention on Human Rights (ECHR), which prohibits punishment for acts or omissions which were not crimes at the time of their commission, as well as punishment in excess of the penalty available at the time.

France
The principle of legality in France (principe de légalité) goes back to the Penal Code of 1791 adopted during the French Revolution. The principle has its origins in the 1789 Declaration of the Rights of Man and of the Citizen, which endows it with constitutional force and limits the conditions in which citizens may be punished for infractions.,

France is also a member of the Council of Europe, and thus subject to Article 7 of the ECHR.

Germany
In Germany, Article 103, paragraph 2 of the Basic Law for the Federal Republic of Germany (German Constitution) bans retroactive criminality: "An action is only subject to a penalty if it was punishable under the law that was in effect before the action was taken."

Enacted after the fall of the Nazi régime, it was reaffirmed in a court decision concerning the actions of East German officials.

Germany is also a member of the Council of Europe, and thus subject to Article 7 of the ECHR.

Switzerland
Article 1 of the Swiss Criminal Code provides that a penalty may only be pronounced for an action expressly forbidden by law.

An "illegal" action may be "licit" in Switzerland if there is a justifying circumstance, such as legitimate defense or necessity.

Switzerland is also a member of the Council of Europe, and thus subject to Article 7 of the ECHR.

United States
In the United States, the Fifth Amendment of the Constitution of the United States contains the concept of due process. Retroactive criminal laws are forbidden in Article I of the Constitution, section 10, paragraph 1.