The first Asian leader to reach Donald Trump by phone after he announced “reciprocal” tariffs in the Rose Garden on April 2nd was To Lam, the general secretary of Vietnam’s Communist Party. He offered to eliminate all tariffs on American goods. Mr Trump praised Mr Lam in a subsequent post on social media. Mr Trump’s tone changed a few days later, however, when Mr Lam welcomed Xi Jinping, China’s leader, to Hanoi for his second state visit in three years. Mr Trump declared that the pair were meeting to work out, “How do we screw the United States of America?”