The Supreme Court of Canada has nullified the result in the closely fought federal riding of Terrebonne, ordering a new byelection in the Montreal-area district.
The decision overturns a previous ruling that had upheld the outcome of last spring’s election, where Liberal candidate Tatiana Auguste secured victory by a single vote following a judicial recount. The seat had initially been declared for the Bloc Québécois on election night.
The dispute stemmed from a mail-in ballot cast by voter Emmanuelle Bossé. CBC News reported that her ballot, marked for the Bloc, was returned due to a misprint on the return envelope. Elections Canada acknowledged the postal code error but maintained the final results had already been certified.
Bloc candidate Nathalie Sinclair-Desgagné challenged the outcome in court, arguing the error denied a valid vote and undermined the integrity of the process. A Quebec Superior Court judge rejected her application in October, describing the mistake as “human error” and not an irregularity under federal electoral law.
On Friday, the Supreme Court reversed that finding after hearing arguments earlier in the day.
“I feel hopeful that democracy has been protected today,” Sinclair-Desgagné told CBC News following the ruling. “Elections Canada not only made a mistake in the postal code, but they also made a mistake in not correcting their mistake.”
Auguste was sworn in after the recount and has represented Terrebonne in the House of Commons since. The court’s decision now creates a vacancy. The Speaker must formally notify the House before the federal government calls a byelection, which cannot occur until at least 11 days after the declaration.
The ruling further complicates the Liberals’ parliamentary arithmetic. At the start of the year, the governing party was within reach of a majority. Two Conservative MPs crossed the floor late last year, leaving the Liberals one seat short of passing legislation without opposition backing.
Recent resignations by former cabinet ministers Chrystia Freeland and Bill Blair have left two additional Liberal seats vacant pending byelections. With Terrebonne now in play, the party sits three seats shy of a majority.
Terrebonne has largely been a Bloc stronghold since the early 1990s. Sinclair-Desgagné represented the riding from 2021 until the contested result. Given its history and razor-thin margins, the upcoming Terrebonne byelection is poised to become a closely watched federal contest.
