Executive Summary
Federal by-elections are held between general elections to fill vacant seats in the House of Commons. Vacancies arise when Members of Parliament resign, pass away, or otherwise leave office before the end of their term. By-elections ensure continued representation for constituents and keep Parliament functioning fully. They are also widely regarded as a mid-term political signal: by-elections typically see lower turnout and can deviate markedly from general election voting patterns, making them a meaningful indicator of where public sentiment stands toward the governing party. This cycle covers three federal ridings: Scarborough Southwest and University-Rosedale in Ontario, and Terrebonne in Quebec. The two Toronto-area ridings are urban constituencies with high population density, diverse electorates, and historically strong Liberal competitiveness. Terrebonne is a different proposition: a suburban Quebec riding northeast of Montreal, where multi-party competition is more volatile and contests between the Bloc Québécois and the Liberals tend to be closer and harder to predict.
Results confirm a clean sweep for the Liberal Party across all three ridings. Scarborough Southwest and University-Rosedale were decided decisively, with Liberal candidates Doly Begum and Danielle Martin securing 69.9 percent and 64.4 percent of the vote respectively. Terrebonne proved the competitive contest anticipated, with Tatiana Auguste holding off Bloc Québécois candidate Nathalie Sinclair-Desgagné by a margin of 731 votes. The broader consequence is structural: with all three seats secured, the Liberals have crossed the 172-seat threshold required for a majority in the 343-seat House of Commons, entering a materially stronger governing position than they have held since the 2025 general election.
Results
Terrebonne– The most unusual vacancy of the three. The 2025 election result was overturned by the Supreme Court of Canada due to ballot irregularities, voiding the outcome and ordering a fresh election. This was not a resignation but a court-ordered rematch, with all major candidates returning to contest the seat a second time.
University-Rosedale- Chrystia Freeland resigned her seat following her appointment as an economic adviser to Ukraine. The former Deputy Prime Minister had held the riding since 2015, leaving a long-held Liberal seat open for the first time in a decade.
Scarborough Southwest Bill Blair vacated the riding upon his appointment as Canada’s High Commissioner to the United Kingdom. The former Minister of National Defence and Toronto Police Chief had held the seat since 2015, departing for a diplomatic post.
Tonight’s results signal a major realignment in federal power-sharing. Liberal victories across all three ridings have secured the current administration a parliamentary majority in the House of Commons, representing a significant departure from minority governance and providing a more stable legislative framework for the Prime Minister Carney’s agenda.
The government no longer depends on opposition support to legislate. It can now advance its program on fiscal policy, major spending, energy and climate, and Canada-United States trade without the procedural uncertainty that defined parliamentary decision-making since 2025. For an administration that has navigated minority constraints for the better part of a year, this is a material change in governing capacity.
Liberal success across two distinct political theatres is notable. The Ontario results confirm dominance in Canada’s largest metropolitan centres with only limited mid-term erosion. The Terrebonne result adds a different dimension entirely: a 731-vote win in suburban Quebec against a well-organized Bloc Québécois campaign demonstrates that Liberal competitiveness in the province extends beyond its urban base. A three-for-three sweep delivers a stronger mandate than two Ontario wins alone would have produced. For opposition parties, the structural challenges remain unresolved. The Conservatives showed no urban foothold, the NDP no path to resurgence, and the Bloc, despite holding nearly 47 percent in Terrebonne, no route to breaking the Liberal majority. The Liberal Party enters the remainder of its term from a position of material strength.