“I don’t know if there is one single interpretation for what Trump is doing. Viewed as a performance to his domestic audience, it makes perfect sense – he’s showing he’s tough on China without actually being in a position to do much concrete damage to relations. He’s a populist who blames global capital and trade competitors for the problems of his core base, so bashing China publicly appeals to them. He doesn’t have to follow it up for a while, and may never do so. Compare this with the Philippine president’s outburst at Barack Obama.

“But there are other interpretations: Trump knows little about diplomacy and is being steered by pro-Taiwan, anti-China hawks. He may have had little idea what calling (or accepting a call from) the Taiwanese president meant.

“Or, Trump is trying to gain favour for property projects he has planned in Taiwan.

“Or, the tweets may be Trump’s way of responding to criticism off the cuff.”