With the exception of involuntary statements, the probative value of evidence does not change because it was obtained illegally. If a court is interested in finding out whether the accused committed the crime charged, throwing out perfectly good evidence because of how it was discovered therefore seems self-defeating. For this reason, the notion that evidence should be excluded simply because it has been illegally obtained has always been controversial. The great American jurist Benjamin Cardozo captured this sentiment with his caustic paraphrase of the American exclusionary rule: "The criminal is to go free because the constable has blundered."1In order to avoid the loss of perfectly good proof and distorted factual findings the common law generally refused to reject evidence because of how it was obtained. Even statements obtained in violation of the voluntariness rule were traditionally excluded not because that rule had been violated but because of the concern that induced statements are unreliable. It was this thinking that led common law
courts to reject involuntary statements but to accept any real evidence that was discovered as a result of those statements. In the leading Canadian common law case of R. v. Wray,2for example, the Court excluded Wray’s involuntary confession but admitted the firearm that Wray’s statements permitted the police to find. Wray’s protest that this was unfair and that judges should have the authority to exclude illegally obtained evidence was repudiated. The Supreme Court of Canada said that it was not unfair to admit the gun into evidence as it was reliable proof that would produce an accurate rather than unfair verdict. In taking this approach the common law courts were not saying that they did not care if police officers broke the law. They were saying that at the trial of the accused, the issue is not whether the police officers acted legally; the issue is whether the accused acted illegally, and relevant reliable evidence on that question should be admitted. The time to deal with the illegality of police conduct is in other legal proceedings about the police officer’s conduct.
The reality, though, was that prosecution and disciplinary action against police officers were rare. As a result, police illegality was most often left unaddressed. Many believed that this harmed the repute of the administration of justice. Citizens were prosecuted for breaking the law, but police illegalities were ignored. The Law Reform Commission of Canada therefore recommended that judges have the discretion to exclude illegally obtained evidence,3but to no avail. It was not until 1982 that things changed with the proclamation of the Charter and the adoption, in section 24(2), of an exclusionary rule for unconstitution-ally obtained evidence.
Since the Charter will be violated by almost any illegal investigative technique, most evidence obtained illegally by state agents is now subject to potential exclusion under section 24(2), Canada’s constitutional exclusionary rule.4This rule, which criminal lawyers have come to
take for granted, was not easily born. Indeed, early drafts of the Charter would have perpetuated the common law position by providing expressly that the exclusion of evidence would not be a remedy for unconstitutional conduct. These early drafts reflected an aversion to an American style rule that excluded crucial evidence, even as a result of minor violations. At Parliamentary hearings, civil libertarians, offended by the empty promise of constitutional rights without remedy, fought against this thinking and lobbied for an exclusionary rule. After much debate, a compromise was reached. It was agreed that unconstitutionally obtained evidence would be excluded, but only in those cases where its admission would bring the administration of justice into disrepute.5As a result...