COMMENT | When I was governor of Hong Kong, one of my noisiest critics was Percy Cradock, a former British ambassador to China. Cradock always argued that China would never break its solemn promises, memorialised in a treaty lodged at the United Nations, to guarantee Hong Kong’s high degree of autonomy and way of life for 50 years after the return of the city from British to Chinese sovereignty in 1997.

Cradock once memorably said that although China’s leaders may be “thuggish dictators,” they were “men of their word” and could be “trusted to do what they promise.” Nowadays, we have overwhelming evidence of the truth of the first half of that observation.

Chinese President Xi Jinping’s dictatorship is certainly thuggish. Consider its policies in Xinjiang. Many international lawyers argue that the incarceration of over one million Muslim Uighurs, forced sterilisation and abortion, and slave labour meet the UN definition of genocide. This wicked repression goes beyond thuggery.

A recent Australian Strategic Policy Institute study based on satellite images indicates that China has built 380 ...