Some of US president-elect Donald Trump's nastiest attacks have been directed at China. He has accused it of "raping" the United States with its trade policies, and of creating global warming as a "hoax" to undermine US competitiveness. Why, then, are many Chinese policy advisers and commentators sanguine about future US-China relations?

The reasoning seems to be that Trump is a businessman, and, to paraphrase former US president Calvin Coolidge, the business of China is business. China, the thinking goes, can work with a swashbuckling dealmaker like Trump better than with a supposedly "ideological" Hillary Clinton. The revelation that Trump and Taiwan leader Tsai Ing-wen spoke by telephone has probably shattered that hope.

It is therefore unlikely the incoming US administration will be anything but a bull in a China shop. That phone call violated a protocol - avoidance of direct contact between the US and Taiwan at the leadership level - which Democrat as well as Republican presidents have carefully observed for four decades.