When an accused person testifies in their own defence, the Crown can ask about prior convictions under the Canada Evidence Act, on the theory that a record says something about credibility. Defence counsel can push back by asking the judge to keep some or all of that record from the jury. That request is known as a Corbett application, after a 1988 Supreme Court case.
Here, a man was fatally stabbed after a night of drinking in an apartment. Nobody saw the stabbing. Of six people present beforehand, only the accused was gone when police arrived, his blood was found in several rooms including where the victim died, and he had a deep cut on his thumb when arrested a week later. The live issues at trial were identity and state of mind.
What the trial judge got wrong
The accused asked to have his record excluded. The trial judge refused, the jury convicted him of second degree murder, and the Court of Appeal upheld it. The Supreme Court took a different view of the judge's reasoning.
Chief Justice Wagner set out how the weighing should work. Convictions involving dishonesty tell a jury something real about whether a witness can be believed. Convictions for violence usually tell them very little about credibility - but carry a high risk of the jury reasoning that someone violent in the past is likely guilty now. That reasoning is exactly what the law forbids. Recency matters too, and so does similarity: the closer a past conviction resembles the current charge, the greater the danger.
Measured against that, the trial judge had overstated the value of several convictions, wrongly factored in how strong the Crown's case was, and should have excluded both the youth offences and several prejudicial violent convictions.
Why the conviction survived anyway
Despite finding those errors, the court dismissed the appeal by applying the curative proviso - a narrow rule that lets a conviction stand where the evidence of guilt was overwhelming and a correctly run trial would have ended the same way. The court was clear this is a rare outcome, not a routine one.
Why it matters
For anyone facing a jury trial with a prior record, this decision gives defence counsel a sharper framework for arguing that old, violent, or youth convictions should stay out. It also signals that appellate courts will look closely at how trial judges conduct that weighing.