Pierre Poilievre, leader of Canada’s Conservative Party, told President Trump to “stay out of our election” on Monday, as voters headed to the polls to determine the future of Canadian governance.

Whatever the case, one thing was clear: Mr. Trump is not giving up on his obsession with Canada, and the new government that emerges from Monday’s vote will need to deal with a leader intent on both hurting Canada’s economy with tariffs, and coveting its vast resources.