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.

China's sharpest pushback on Sunday was over fentanyl, an area where the Biden administration had also been urging Beijing to crack down on shipments.

Robert Lighthizer, who was the U.S. trade representative in President Trump's first administration, says China poses an existential threat to the United States that must be urgently addressed by Washington.