The U.S. ambassador to China will step down early next month, ending a three-year tenure marked by a trade war and increasingly bitter relations between the world’s two largest economies. Terry Branstad, appointed by President Donald Trump in 2017, confirmed his decision in a phone call with Trump last week, the U.S. Embassy said in a statement Monday. Word of his departure leaked out earlier in the day when Secretary of State Mike Pompeo thanked Branstad on Twitter for his service.