Supreme Court Invalidates Terrebonne Election Result

OTTAWA - The Supreme Court of Canada ruled Friday that the result of the federal election in the Terrebonne riding near Montreal is invalid, vacating the seat held by Liberal Member of Parliament Tatiana Auguste and paving the way for a by-election after a clerical error disenfranchised at least one voter.

The decision overturns Auguste's narrow victory by a single vote over Bloc Québécois candidate Nathalie Sinclair-Desgagné in the April 28, 2025, general election. Sinclair-Desgagné, the incumbent MP at the time, had appealed the outcome, arguing that an Elections Canada mistake prevented votes from being counted. The court, in a ruling announced following oral arguments, determined that the error constituted an electoral irregularity under federal law, even without evidence of intent or malice.

The controversy stemmed from issues with special mail-in ballots. An Elections Canada employee entered an incorrect postal code on envelopes for some ballots from the riding, causing at least one to be returned undelivered. A female voter in Terrebonne later reported that she had mailed her ballot supporting the Bloc Québécois, only to receive it back after election day, meaning her...