Donald Trump is back in the White House, promising to use the United States's vast economic weight to hit back at China for its alleged unfair trade practices and role in the deadly American fentanyl crisis.

President Donald Trump is considering changing a key U.S. trade benefit to other nations, the "de minimis" exemption on import tariffs, as he accuses China of unfair trade practices and blames it for a crisis over the deadly drug fentanyl.

Only a third of China’s trade surplus was with the United States, and only a third of the U.S. deficit was with China. That makes for tricky math for the president-elect.