A divided court splits 6-3 on whether an Elections Canada typo was serious enough to undo a riding decided by one vote
A divided Supreme Court of Canada has explained why it annulled Terrebonne’s 2025 federal election from the bench in February.
The riding was decided by a single vote and undone by a single ballot that was never counted.
The court allowed the appeal on Feb. 13, 2026, at the close of oral argument, vacating the seat that day with reasons to follow. Terrebonne voted again on April 13 and returned Liberal Tatiana Auguste, who had won the annulled election by one vote. This time her margin was roughly 700 votes.
The reasons in Sinclair-Desgagné v. Canada (Chief Electoral Officer), released on Sept. 18, split the court 6-3.
The case originated with an Elections Canada worker preparing address labels for mail-in ballot return envelopes. He typed the wrong final three characters of the polling station’s postal code.
The worker noticed the error on April 6, three weeks before the vote. He corrected the labels on the kits still in the office and destroyed the defective ones that had not gone out. But he did not tell his supervisor, nor did he try to contact the electors – at least 40 by his own estimate – whose mismarked envelopes had already been mailed.
One of those envelopes, addressed to Emmanuelle Bossé, was returned by Canada Post with the label "moved / unknown." Her ballot was never counted.
Sinclair-Desgagné sought an annulment from a Quebec Superior Court judge, who dismissed her application, holding that an honest clerical slip without dishonest or malicious intent was not an "irregularity" under the Canada Elections Act. The court added that it would not have annulled the election in any event.
Using special provisions in the Act that grant a right of appeal directly to the Supreme Court within eight days, Sinclair-Desgagné bypassed the Quebec Court of Appeal and went straight to Ottawa.
Justice Mahmud Jamal, for the majority, ruled that an irregularity can include a serious administrative error that is honest and unintentional and that breaches no statutory provision; the question is whether the error could undermine a voter’s franchise.
Here, Elections Canada caused the error, knew about it for three weeks, had the ability and the responsibility to fix it, and did nothing. With one affected ballot against a one-vote margin, the result could not stand.
The Superior Court had reasoned that counting Bossé’s ballot would have produced a tie. That was itself an error, the majority said: ballot secrecy precludes any investigation into how a voter actually marked her ballot, and that bar applies at every step of the analysis, not only when a court decides whether to annul.
Arthur Hamilton, in Dentons Canada LLP’s litigation and dispute resolution group in Toronto, says the split decision exposes a fault line in how the public views the court’s role regarding election results.
"The majority and the dissent have competing instincts about what most people feel about courts undoing elections. Which one is persuasive being largely in the eye of the beholder."
The majority’s view holds that a voter who did everything asked of her should not lose her vote to the state’s mistake and failure to correct it. The dissent reasons that elections should not be reopened over a typo.
The dissent, written jointly by Justices Andromache Karakatsanis and Sheilah Martin with Justice Mary Moreau concurring, anchors its reasoning in the Canada Elections Act. The statute provides that an elector who votes by special ballot "shall ensure" the ballot is received on time and has the "sole responsibility" to do so.
Nothing in that text, the minority concluded, limits the elector’s responsibility when Elections Canada or anyone else makes an error. Bossé had a tracking number. She did not use it, nor did she vote in person.
The dissenters also warned about the impact of the majority’s conclusion: If a mistake of this size was enough to reopen an election, they wrote, it was hard to see what kind of error would not meet the bar – putting every result at risk and undermining the stability, certainty and finality of elections.
"The problem is that I doubt you could find 10 Canadians who know the provisions cited by the minority exist," Hamilton said.
The majority held that the relevant statutory provisions were aimed at contingencies outside Elections Canada’s control – postal delays, a voter who mails late – and not as a waiver for errors the agency itself made and could fix.
Bossé had applied for the mail ballot, received her kit, marked her ballot and mailed it 22 days early in the envelope Elections Canada told her to use. Her duty, the majority said, did not extend to second-guessing official materials handed to her by the government.
Hamilton sees the official’s three weeks of silence – no report to his supervisor, no contact with the affected electors – as what animated the majority.
"The majority just wasn’t prepared to condone that type of thing."
But the majority was careful to point out that the decision to annul did not disturb the governing principles found in the court’s 2012 decision in Opitz v. Wrzesnewskyj.
"Opitz was a case about the pursuit of perfection – the court was unwilling to let elections be settled by enterprising lawyers combing through the paperwork of individual votes – and emphasized the judiciary’s reluctance to interfere with electoral results," Hamilton says. "Nothing in today’s decision disturbs that."
Thomas Barlow, who, with co-counsel Chris Semerjian and Marie-Eve Labonté of Fasken Martineau Dumoulin LLP, represented Adrienne Charles, the respondent and Conservative candidate who placed third in the original election and supported the case for an annulment, agrees.
“The decision is built on Opitz, interprets the principles correctly, and is very consistent with it,” he says.
Indeed, Justice Jamal was careful to note, the instant case involved the extremely rare combination of a single confirmed lost ballot and an election decided by one vote.
"What the majority has done is recognize a specific mischief – admitted inattention to a known, correctable official error – with consequences that could not be ignored, and, on that narrow basis, annul very reluctantly," Hamilton says.
