‘Unreasonable’ to cancel election won by single vote, lawyer for Liberal MP says

MONTREAL — The lawyer for a Quebec Liberal MP who won her riding in the April federal election by a single vote argued on Tuesday it would be unfair to other voters to cancel the result over one uncounted ballot.

Marc-Étienne Vien, lawyer for MP Tatiana Auguste, told a hearing in St-Jérôme, Que., that ordering a new election would be “unreasonable” and would effectively disenfranchise the tens of thousands of people who cast ballots in the Terrebonne riding, north of Montreal.

“To cancel the election is to deny the right to vote that was expressed by these 61,115 people,” Vien said in Superior Court.

If a new vote were held, he said, some of the people who cast ballots in April may have since died or would be otherwise unable to vote in a new byelection.

The Quebec Superior Court agreed to hear the case after former Bloc Québécois candidate Nathalie Sinclair-Desgagné challenged the election results in the riding. She launched the challenge after a Bloc voter revealed that her special ballot was returned to her — and not counted — because of an error in the address on the envelope provided by Elections Canada.

Auguste initially won the riding, but it flipped to Sinclair-Desgagné after the votes went through a validation process. A judicial recount completed on May 10, however, concluded the Liberals had won the riding by one vote.

Sworn statements filed in the case show that an election employee discovered he had mistakenly printed his own postal code on several special ballots about three weeks before the election day.

Vien told the court that there are well-known risks to voting by mail, and that by law, it’s not Elections Canada’s responsibility to ensure mail-in ballots arrive at polling stations. Vien described the error as “banal,” and said human error can happen to anyone and result in a few votes not being counted for a variety of reasons.

“These are things that happen,” he said. “To allow a contestation of elections on this basis doesn’t seem appropriate.”

He also said it’s not a given that the ballot in question affected the outcome of the election.

He said three ballots marked for the Bloc Québécois were found in garbage cans at the polling station, and that they were included in the final vote tally despite not being placed in the ballot box by the voter. He suggested those votes could be discounted because their authenticity could not be confirmed — meaning Auguste’s margin of victory should have been four votes and not one.

Sinclair-Desgagné’s lawyer, Stéphane Chatigny, said the one-vote decision corresponded to a margin of victory of 0.000016.

“I submit that this is the illustration of the degree of certainty we have in the identity of the winner of the election in Terrebonne,” he said.

Denying an eligible voter the right to vote constitutes an irregularity that affected the outcome of the election, he said, pushing back against the suggestion that the error was banal.

A lawyer for Elections Canada told the hearing that he would not take a position on Sinclair-Desgagné’s challenge. He said the organization acknowledged that an error had taken place during the election. David Baum referred to a 2012 Supreme Court of Canada decision that set a high bar for annulling elections based on administrative errors.

The decision, he said, found the right to vote to be of utmost importance, but it also concluded that elections in Canada are “not designed to achieve perfection.”

“It’s a big, complex machine, and errors are inevitable,” Baum said.

This report by The Canadian Press was first published Oct. 21, 2025.