A criminal law or a regulatory offence can be declared invalid by the courts if it results in an unjustified violation of a Charter right, such as freedom of expression. Expression has been interpreted broadly to include non-violent attempts to convey meaning. Thus, offences prohibiting hate literature, communication for the purposes of prostitution, defamatory libel, or pornography must be justified by the government under section 1 of the Charter as a reasonable limit on the Charter right.
The principles of fundamental justice in section 7 of the Charter have been interpreted as prohibiting the use of vague, aribtrary, over-broad, or grossly disproportionate laws. Section 7 of the Charter also prohibits the punishment of the morally innocent who are not at fault, as well as those who act in a morally involuntary manner in dire circumstances where there was no other realistic choice but to commit the crime. The question of what constitutes moral innocence is quite complex and depends very much on the particular context. What is required under section 7 of the Charter to sustain a conviction for murder or war crimes is quite different from what is required to sustain a manslaughter conviction. It is also quite different from what is required for a conviction of a regulatory offence, such as misleading advertising.