A unified North American trading powerhouse has long been seen as a potential bulwark against China. But Trump has repeatedly threatened to take over Canada and has targeted Mexico with some of his toughest tariffs. New Canadian Prime Minister Mark Carney has warned that his country’s traditional relationship with Washington is over.

On Tuesday, President Donald Trump bragged that many foreign leaders were “kissing his ass” to avoid the steep tariffs he’d imposed on their countries. But China’s leader, Xi Jinping, was not one of them. “We are waiting for their call,” Trump said of China’s leadership in a social-media post.

Beijing, which imports far fewer goods from the U.S. than it exports, is considering a range of nontariff measures amid growing trade tensions between the world’s two biggest economies.