OTTAWA — Prime Minister Mark Carney’s Liberals won a federal election Monday, the country’s public broadcaster, the CBC, projected, an extraordinary comeback that was fueled in part by President Donald Trump’s tariff policies and attacks on Canada. Just months ago, Carney’s party was headed for a potentially historic drubbing. It was not yet clear whether the Liberals would rule a minority or majority government as votes continued to be counted. This is the fourth consecutive Liberal government since 2015. Amid the U.S. president’s trade war and threats to annex its northern neighbor, voters flocked to Carney — a political novice,...