Spring By-Elections Could Hand Carney Liberals a Majority by a Single Seat
Prime Minister Mark Carney will face his first electoral test since assuming the Liberal leadership when voters head to the polls in three federal ridings on April 13, with by-elections triggered by resignations and a rare judicial nullification of a 2025 result.
The vacancies present both opportunity and peril for the new prime minister. While the Liberals are widely expected to retain their traditional strongholds in Scarborough Southwest and University—Rosedale, the Quebec riding of Terrebonne represents a wild card that could determine whether Carney governs with a razor-thin minority or gains critical breathing room in a closely divided House.
In University—Rosedale, voters will choose a successor to Chrystia Freeland, who resigned her seat in January to take an advisory role with the Ukrainian government. The Liberals have nominated Dr. Danielle Martin, a prominent physician and healthcare advocate known for her work defending public medicine.
Martin's academic pedigree and high public profile align well with a riding that includes the University of Toronto campus and numerous healthcare institutions. The seat has been Liberal since its creation in 2015, and party strategists express confidence in their candidate's ability to hold the riding.
The Scarborough Southwest contest features an unusual political crossover. Former Ontario New Democratic Party (ONDP) deputy leader Doly Begum will carry the Liberal banner following the resignation of Bill Blair, who departed in February after being appointed High Commissioner to the United Kingdom.
Begum represented the provincial riding of Scarborough Southwest for the ONDP at Queen's Park before crossing paths with federal Liberals. Her name recognition in the area is considered strong, though political observers note the adjustment from NDP to Liberal branding will be tested at the ballot box.
Complicating the race is neighbouring federal Liberal MP Nate Erskine–Smith, who represents the adjacent riding of Beaches—East York. Erskine-Smith has announced his intention to resign his federal seat to seek provincial office in the same Scarborough Southwest riding Begum represented.
The Riding Where One Vote Changed Everything
The most closely watched contest will unfold in Terrebonne, where the by-election stems from circumstances unprecedented in recent Canadian political history.
In February, the Supreme Court of Canada invalidated the 2025 election result that saw Liberal Tatiana Auguste defeat Bloc Québécois candidate Nathalie Sinclair-Desgagné by a single vote. The court acted after it was revealed that a mail-in ballot cast for Sinclair-Desgagné was rejected because an election worker recorded an incorrect postal code.
The Bloc Québécois challenged the result, and the Supreme Court ultimately agreed the administrative error deprived Sinclair-Desgagné of a fair chance at victory. In a sharply worded decision, the court emphasized the need to ensure "the right person is sitting in the House of Commons" and ordered a new vote.
Auguste, who briefly sat as the member for Terrebonne before the ruling, will again carry the Liberal banner. The riding, located northeast of Montreal, has alternated between Bloc Québécois and Liberal representation in recent elections, reflecting its status as a bellwether for Quebec political sentiment.
What The Results Could Mean for Carney's Liberals
The arithmetic in Ottawa lends outsized importance to the Terrebonne outcome. Following the departures of Freeland and Blair, and after three Conservative MPs crossed the floor to join the Liberals since winter 2025, the current standings sit at 169 Liberals against 171 combined opposition members.
Winning both Toronto ridings would bring the Liberals to 171 seats, exactly tied with the opposition, though the Speaker traditionally votes with the government to break ties. Holding Terrebonne would give the Liberals 172 seats and an effective working majority.
Losing any of the three seats would complicate Carney's position, but losing Terrebonne carries particular sting. A Bloc Québécois victory there would not only deny the Liberals a potential majority but would hand a morale-boosting win to a party eager to assert its dominance in Quebec.
The by-election writs drop immediately, triggering a five-week campaign that will test Carney's coattails, the strength of the Liberal brand in Quebec, and whether high-profile candidates can translate personal popularity into votes. Polling stations open April 13th, with results expected that evening.
