U.S. President Trump recently claimed Washington’s trade war with China has had little impact on the American economy so far. A widely followed economist said that the president is “dead wrong.”

Trump said in a Wednesday Twitter post that the U.S. is “winning, big, time against China,” adding that “prices to us have not gone up, and in some cases, have come down.”

However, according to Mark Zandi, chief economist at Moody’s Analytics and a frequent critic of the Republican president, the “economic costs are mounting” in the U.S. “To argue that this isn’t doing economic damage is just wrong,” Zandi told.

If Trump were to follow through on his outstanding tariff threats, Zandi said, it would incur a cost of $100 billion for American businesses and consumers in the coming year. “That’s half a percent of (gross domestic product), that’s about half the tax cut that Americans got last year,” the economist said. “That’s very significant.”

At some point, Zandi said, Trump is likely to realize that the hard-line stance on China in the trade war “isn’t working” and so the president will desire a “face-saving way” out of the situation. “The question is, will (Chinese) President Xi (Jinping) give him the way out? ” Zandi asked.