Every writer on China knows that even mild public criticism of the middle kingdom generates vitriolic and sometimes deranged responses from Chinese nationalists. Among the more printable reactions to my previous column was an e-mail suggesting that I had an ingrained hatred of China and asking whether I had been castrated or my ancestors bullied by Beijing.

Such anger, erupting spontaneously in messages from people who can rarely be drawn into a reasoned debate, illustrates a problem lying at the heart of Chinese foreign policy: the absence of vigorous public debate inside China on the important international issues of the day.