How Justin Trudeau lost his grip

Justin Trudeau could lose Canada’s next election because he’s just not as angry as the country he leads.

The prime minister has been getting smoked in the polls. His rival is a savvy and fiery conservative dismissed at the outset by Trudeau’s inner circle as too cantankerous for mainstream appeal.

In the year since taking over Canada’s Conservatives, Pierre Poilievre has tapped grievance politics and assembled a coalition of populists, social conservatives and center-right moderates that would make him the favorite if a vote were held any time soon. Conservatives sit ahead...