If anyone has been more galvanised than the foreign policy community by Donald Trump’s apparent willingness to dispense with diplomatic niceties in Asia, it is his legions of fans in mainland China.

By taking a phone call on Friday from Taiwan’s president Tsai Ing-wen, Mr Trump broke with decades of precedent and upended a careful word game that allows the US to recognise a single China, ruled from Beijing, while at the same time preserving the breakaway island’s democratic self-rule. He followed up on Sunday with tweets bashing China’s island-building in the South China Sea and the value of its currency.

That has convulsed Mr Trump’s Chinese supporters, who had backed the reality-TV star for his outspokenness, in contrast to what they saw as the “politically correct” attitudes of Hillary Clinton.