Open this photo in gallery: Prime Minister Justin Trudeau speaks with Stellantis auto assembly workers during a tour of the Windsor Assembly Plant in Windsor, Ont. on Jan. 17.REBECCA COOK/Reuters Ottawa and Queen’s Park are getting played by Stellantis STLA-N, but you can’t say they didn’t ask for it. By deciding to engage in a subsidy war with the United States, Prime Minister Justin Trudeau and Ontario Premier Doug Ford ensured they would be held for ransom. Politically, they have no choice now but to pay up. Mr. Ford and Mr. Trudeau have boasted so much about attracting electric-vehicle investments,...