MONTREAL — Even as the party falters everywhere else in Canada, Prime Minister Justin Trudeau’s Liberals have been able to take solace in the party’s strongholds in Quebec, despite aggressive attacks from the Conservatives and the Bloc Québécois.

One more nail could be driven into the Liberal coffin on Monday, though, if the party falters in a Montreal byelection that would be an easy victory in better times. But, if the party’s most prominent face in Quebec is worried, he’s not showing it.