PQ candidate Alex Boissonneault wins Arthabaska byelection

Analyst Raphaël Melançon says the Arthabaska byelection result is 'a very important victory' for the PQ, which he says is the leading political force in Quebec.

The Parti Québécois won its third consecutive byelection with a victory in Arthabaska, a humiliating defeat for the Legault government, which had held the riding since 2012.

The PQ candidate, former Radio-Canada journalist Alex Boissonneault, will therefore make his debut in the Salon rouge.

Boissonneault presented himself as a centre-right politician who wants to repair the social contract between the state and its citizens. According to him, Quebecers are not getting the services they pay for.

During the campaign, he regularly reminded voters that he was born in Saint-Ferdinand and grew up in Victoriaville.

This is another blow to the Coalition Avenir Québec, which is losing a riding it has held for more than 10 years. In 2022, CAQ candidate Eric Lefebvre won the riding with 52 per cent of the vote.

Premier François Legault conceded defeat shortly after 9 p.m., even before the winner’s name was known.

He said he would take “full responsibility for the defeat.”

“Over the next few weeks, we will look in the mirror and take full responsibility for the disappointment of Quebecers, and we will make changes,” he said at a press conference.

Legault was in Victoriaville alongside his defeated candidate, Keven Brasseur.

With Arthabaska, the PQ continues its momentum started by its victories in Jean-Talon and Terrebonne.

However, this is a short-lived victory for the new PQ member, who will have to quickly return to door-to-door campaigning to keep his seat, as the next general election will be held in October 2026.

The PQ has been leading in the polls since the end of 2023. Last Friday, PQ leader Paul St-Pierre Plamondon assured that he would give Boissonneault “important responsibilities” in a future PQ government and that he had “what it takes” to be a minister.

It is also a heartbreaking defeat for Conservative leader Éric Duhaime, who was hoping to finally make his debut in the National Assembly.

In the 2022 general election, the Conservatives won 13 per cent of the vote but no seats. The Conservative leader often claimed during the campaign that a victory in Arthabaska would go some way toward compensating for this “democratic distortion.”

This report by The Canadian Press was first published in French on August 11, 2025.