Supreme Court Nullifies Liberal MP’s Election Win By a Single Vote in Quebec Riding

The Supreme Court of Canada has overturned the election outcome in the Montreal-area riding of Terrebonne where a Liberal MP secured victory by a single vote in April 2025.

A new byelection must now be held for the riding, which has historically been represented by the Bloc Québécois.

Liberal candidate Tatiana Auguste was declared the winner in the riding by a single vote over Bloc MP Nathalie Sinclair-Desgagné. The Bloc later filed a legal challenge, requesting that the courts invalidate the results and call a new election. The call came after reports of a voter getting her mail-in ballot sent back because of a misprint on the return envelope.

Terrebonne resident Emmanuelle Bossé told several media outlets she mailed in her vote supporting the Bloc weeks before the April 28 election, but it was returned to her on May 2 because Elections Canada had placed the wrong return address on the envelope.

Elections Canada also confirmed to The Epoch Times that the local riding office received 115 special ballots, but that five of the ballots were received late “even though the return envelope contained an error in the postal code.”

Auguste was initially declared the winner in Terrebonne on April 28 by 35 votes, but the vote tabulation later determined on May 1 that incumbent Sinclair-Desgagné had won re-election and beat Auguste by 44 votes.

Elections Canada announced on May 7  that a judicial recount would take place for the riding, which is mandated in situations where the vote difference between two candidates is less than 1/1,000 of the total votes cast. Following the recount, it was announced on May 10 that Auguste had won the riding by a single vote.

A Superior Court judge rejected Sinclair-Desgagné’s call for another byelection in October 2025, arguing that a postal code mishap amounted to human “error” and did not constitute an irregularity as defined under the Elections Canada Act. But the Supreme Court overturned that ruling after hearing arguments this week.

The Supreme Court said it will release its written reasons for the decision at a later date.

The recent ruling puts the Liberal Party further from a majority government of 172 seats. Conservative MPs Chris d’Entremont and Michael Ma had crossed the floor in late 2025, putting the party just one seat away from a majority. Tory MP Matt Jeneroux also announced that he planned to resign this spring,

The resignations of cabinet ministers Chrystia Freeland and Bill Blair in recent weeks means the Liberals are now three seats away from a majority, and byelections will be held for the vacant seats.

The seats once held by Freeland and Blair have been occupied by the party since 2015 and are seen as secure, but the Quebec riding of Terrebonne has been held by the Bloc since 2015.

The Epoch Times contacted the offices of Sinclair-Desgagné and Auguste for comment but did not hear back before publication.