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Pressure is mounting on Quebec Premier François Legault to step down, with only a quarter of Quebeckers saying that they approve of his performance.Jacques Boissinot/The Canadian Press

At the onset of the COVID-19 pandemic, François Legault was Canada’s most popular premier. With an approval rating that peaked at 85 per cent, Mr. Legault appeared to walk on water. Prominent members of Quebec’s sports and entertainment star system rallied behind the Coalition Avenir Québec Leader as they urged the public to obey his anti-COVID rules.

Five years can seem like a millennium in politics. But his hero-to-zero descent in the polls has been stunning nonetheless. He is now Canada’s most unpopular premier, with only a quarter of Quebeckers saying that they approve of his performance. After winning a second majority government in 2022, and 90 of the National Assembly’s 125 seats, his CAQ is now facing annihilation in next year’s provincial election.

Indeed, Mr. Legault seems to be following in Justin Trudeau’s footsteps as pressure mounts for him to step down before the next vote. So far, he has insisted that his resignation is not in the cards and, with no heir apparent waiting in the wings, he has been able to hold on. That could change after Monday’s by-election in the riding of Arthabaska, a semi-rural riding south of Trois-Rivières in what used to be solid CAQ country.

The contest to replace the former CAQ MNA, Eric Lefebvre, who is now the local Conservative MP in Ottawa, is expected to be a two-way race between the Parti Québécois and the Quebec Conservative Party, whose leader, Éric Duhaime, hopes to become his party’s first elected MNA.

Mr. Lefebvre won almost 52 per cent of the popular vote in the 2022 election, but CAQ candidate Keven Brasseur will be lucky to crack double digits this time around. The upstart provincial Conservatives finished second in the last election with about 25 per cent of the vote. But with Mr. Duhaime, whose libertarian rhetoric has made him an eccentric, if polarizing, sensation on the Quebec political scene, the party could be poised for a breakthrough.

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There is strong anybody-but-Duhaime sentiment in parts of the riding, and Mr. Duhaime’s calls for Quebec to abandon carbon pricing and electric-vehicle mandates, allow for more private health care and slash government spending has made him the principal target of the PQ candidate, Alex Boissonneault. He is likely to benefit from strategic voting by centrist and left-of-centre voters seeking to deprive Mr. Duhaime of a coveted foothold in the legislature.

Mr. Boissonneault’s past – he was arrested in 2001 for plotting to disrupt the Summit of the Americas in Quebec City – does not appear to have hurt his chances of scoring a third successive by-election win for the PQ. He has chalked up his far-left activism as an “error of youth” and pointed to his subsequent career as a Radio-Canada journalist as proof that he has “lived a respectable, clean life.” He left the public broadcaster in June to run for the PQ.

The race between Mr. Boissonneault and Mr. Duhaime could come down to which party’s agenda voters fear most: the PQ’s promise to hold another sovereignty referendum if it wins the 2026 election, or the hard-right turn promised by Mr. Duhaime’s Conservatives.

A PQ win in Arthabaska would fuel the party’s momentum as it prepares for the election in the fall of 2026, helping it attract star candidates and donations for next year’s race.

Under Leader Paul St-Pierre Plamondon, the PQ has led the polls for months. And while the Quebec Liberal Party has seen its own numbers rise since the June election of former federal Liberal cabinet minister Pablo Rodriguez as its new leader, the QLP remains far behind the PQ in francophone Quebec, which typically determines election winners.

For his part, Mr. Legault is promising a major cabinet shuffle before the National Assembly returns in mid-September. It could be his last chance to reboot his own political career.

The Premier has been badly damaged by a public inquiry over mismanagement at the provincial automobile insurance board and by the bankruptcies of local electric school bus manufacturer Lion Electric and Swedish electric-battery maker Northvolt, which had promised to build a plant in Quebec. Both corporate failures are expected to cost the Quebec government hundreds of millions of dollars in lost subsidies.

“I think you need to be living on another planet not to see that Quebeckers are disappointed” with the CAQ, Mr. Legault conceded as the legislature began its summer recess in June. He vowed to correct course by fall.

There is speculation that Mr. Legault will move forward with the recommendations of a panel on Quebec’s autonomy that called for the drafting of a Quebec constitution. He is also expected to slash the number of permanent residents Quebec accepts. But it will take a lot more than that for him to avoid Mr. Trudeau’s fate.