US Trade Representative Jamieson Greer was spending a second day testifying to Congress on what the Trump White House insisted was a trade “emergency” that needed unprecedented action. But he learned about his boss’ about-face during the hearing, in an episode that shattered his credibility in future trade talks.

Facing a global market meltdown, President Donald Trump on Wednesday abruptly backed off his tariffs on most nations for 90 days, but raised his tax rate on Chinese imports to 125%