The United States sought the extradition of the respondents for a plane hijacking allegedly committed in 1969.
At the time, hijacking was not a crime under Canadian law nor an extradition crime under the existing treaties, but it was later added to the Criminal Code and the 1976 extradition treaty.
The Supreme Court of Canada held that while the treaty applies to crimes committed before it came into force, a fugitive may only be extradited if the act was a crime recognized in Canada at the time it was committed.
The appeal was dismissed.