Section 7 of the Charter and the Common Law Rules of Evidence

The advent of the Charter coincided with the Supreme Court of Canada’s development of a principled approach to the common law of evidence. Over the past 25 years, the Court has forged an important connection between these two changes in the law. When the Court has dealt with constitutional challenges to statutory changes to the common law of evidence, it has tended to reject the claim that the statute is unconstitutional, but has also tended to vindicate the values underlying the common law rule at issue by interpreting the statutory rule to preserve the trial judge’s discretionary power to exclude evidence on the ground of excessive prejudice. In this way, the Court has effectively constitutionalized the common law discretion to exclude evidence where its probative value is outweighed by its prejudicial effect. The development of this link between the Charter and the common law of evidence has not gone so far as recognizing a constitutional right to the exclusion of patently unreliable evidence. However, closer attention to the general principle that excessively prejudicial evidence is inadmissible could lead to a reversal of some recent undesirable developments in the common law confessions rule