1. The Principle of Legality

The principle of legality is a cornerstone of criminal justice. Although its implications are many, the basic idea is that one should only be prosecuted for crimes that exist in law. Codification is supposed to make it clearer to everyone what the offenses are at any given time, but that implies that codes be up to date! The principle has a strong democratic component: it is not only that the criminal law should be 'in" or "part of" the law, it is also that if we are going to punish people, perhaps the greatest liberty a society can take with their fundamental rights, then at the very least the Parliament should be involved, adopting actual laws.

The principle has implications for the sources of criminal law, as well as interpretation. For example, whilst the Canadian Charter of Rights should be interpreted teleologically, offenses are to be interpreted restrictively. Reasoning by analogy, whilst generally accepted in civil matters is seen with suspicion when it comes to criminal offenses. Having said that, the courts will often be mindful of Parliamentary intention in interpreting restrictively, especially if too restrictive an interpretation will lead to manifestly unreasonable results.

The temporal element is a crucial element of the principle of legality. The key insight is that one should never be accused of having committed an offense that was not an offense at the time it is alleged one committed it. In other words, substantive criminal law can never be retrospective. The only exception is in cases where a subsequent law is actually less punitive/more liberal, in which case Parliament may provide the benefit of the new regime to past offenders.

One of the central issues is whether, all things considered, defendants had been given "fair notice" of the existence of an offense. In extreme circumstances, the Canadian Supreme Court may strike down offenses merely because they are too vague, but only once it has sought to interpret the relevant provisions. Note that, in the background, ignorance of the law is never a defense to criminal charges. What one needs to allege to argue successfully that the principle of legality was violated, is typically that one could not have known the law. Case and code based systems of criminal law may not be entirely equal in their ability to signal what the law is, but there is no doubt that even a common law system based on precedent can in theory satisfy the requirements of fair warning. Similarly, there may be an argument that a decentralized system such as international law is less good at indicating what the offenses are, although given the gravity of offenses in such cases and the fact that they overlap with domestic crimes it may be difficult for defendants to argue that what they did was not criminal.

Class preparation:

Criminal Code of Canada:
9. Notwithstanding anything in this Act or any other Act, no person shall be convicted or discharged under section 736
(a) of an offence at common law,

ICC Statute

Article 22 of the Statute of the International Criminal Court:
Nullum crimen sine lege

1. A person shall not be criminally responsible under this Statute unless the conduct in question constitutes, at the time it takes place, a crime within the jurisdiction of the Court. 

2. The definition of a crime shall be strictly construed and shall not be extended by analogy. In case of ambiguity, the definition shall be interpreted in favour of the person being investigated, prosecuted or convicted. 

3. This article shall not affect the characterization of any conduct as criminal under international law independently of this Statute. 

Article 23
Nulla poena sine lege

A person convicted by the Court may be punished only in accordance with this Statute.

Article 24
Non-retroactivity ratione personae

1. No person shall be criminally responsible under this Statute for conduct prior to the entry into force of the Statute.  

2. In the event of a change in the law applicable to a given case prior to a final judgement, the law more favourable to the person being investigated, prosecuted or convicted shall apply