As the leaders of Canada and Mexico rushed to respond after Donald Trump started a new trade war, Chinese President Xi Jinping took a breath before his nation announced any concrete retaliation.

Canadian officials have said that the goods have been selected with an eye to maximizing the effect of their retaliation in Republican-controlled states, in a bid to get representatives from those states to weigh in with Mr. Trump and ask him to call off U.S. tariffs and de-escalate.

China's government on Sunday denounced the Trump administration's imposition of a long-threatened 10% tariff on Chinese imports while leaving the door open for talks with the U.S. that could avoid a deepening conflict.