Donald Trump removed any remaining doubts that he is serious about steep new tariffs on Chinese imports on Friday by asking Robert Lighthizer to return as his trade representative. Lighthizer is a lawyer who cut his international trade teeth fighting Chinese steel dumping in defence of the US steel industry, and he blames free trade for the hollowing out of manufacturing across the Midwest. But it remains unclear if Trump wants the tariffs because he believes in them as a net plus for the US economy (smarter people note they will simply fuel inflation) or because he sees them as a route to leverage over Xi Jinping. Wu Xinbo, an adviser to China’s foreign ministry, told a conference late last week that Beijing wants a deal. No wonder. The 40-year Sino-American megatrade of cheap goods in US stores in return for bottomless Chinese dollar reserves is what lifted 500 million Chinese out of poverty.