Sinclair-Desgagné was elected to represent the
riding of
Terrebonne in the
House of Commons in the
2021 federal election as a member of the
Bloc Québécois. She served as the critic of public finances, pandemic programs and Canada Economic Development for Quebec Regions in the
Bloc Québécois Shadow Cabinet. In the
2025 federal election, the initial count completed the day after the election showed Sinclair-Desgagné
losing her seat to
Liberal candidate
Tatiana Auguste, but
Elections Canada's validation process revised the results, instead giving Sinclair-Desgagné a 44-vote victory. Because of the narrow margin, a
judicial recount was automatically triggered. The recount, completed on May 10, flipped the result again, confirming Auguste as the victor by a margin of a single vote. Sinclair-Desgagné said she would contest the result after a Bloc voter disclosed that her mail-in ballot had been returned to her due to a postal code misprint on the envelope provided by Elections Canada. After Elections Canada said that it did not have
legal standing to change the result, the Bloc announced on May 15 that it would seek a court order for a new by-election. The same day, Elections Canada stated that five other mail ballots with the incorrect returning address printed had been rejected because they had arrived at the Elections Canada office in the riding after the deadline; the statement said that it could not determine if the incorrect address was responsible. The election result was upheld on October 27 by the
Superior Court of Quebec. On November 3, Sinclair-Desgagné announced that she would be appealing the ruling to the
Supreme Court of Canada. On February 13, 2026, the Supreme Court annulled the result of the election in the riding, leaving the seat vacant. Auguste won the
ensuing by-election on April 13 by 668 votes.
Electoral record ==References==