US president-elect Donald Trump is usually described as a pragmatic and successful businessman - a man who knows how to cut a deal to his own advantage.

So it has been strange to hear him say that he wants to use the US' continued observance of the one-China principle regarding Taiwan as a bargaining chip in trade talks with Beijing, because that has no leverage. Taiwan is part of China no matter what he says.

However, since he has indicated with his pre-office sound bites that his real interest is trade, let's talk about trade.