From here, Beijing’s choices in Hong Kong will not grow easier. The ultimate option, of course, is to mount a police or military intervention from the mainland in order to put down the protests. But at what cost? Hong Kong would lose forever its status as a global, cosmopolitan city, a goose that lays golden eggs for China. Since Deng Xiaoping introduced capitalism to China, Hong Kong has served as a critical business and investment portal for the country: a place where foreign companies feel it is safer for them to be based because of the independent judicial system and a banking structure that allows the free conversion of currencies and unlimited international transfers. As China has grown vastly richer it has become less dependent on Hong Kong for such purposes, but lots of investment into China still passes through the city.

A takeover of Hong Kong by force would also destroy Beijing’s proposition – tattered as it may already be – that Taiwan should accept unification with China on the basis of one country, two systems. Recent events in Hong Kong have already strongly lifted the election prospects for the governing party in Taiwan, whose leader Tsai Ing-wen favours continued defiance of Beijing.

Most unpredictable, though, is how this will play in China itself. A catastrophic crackdown in Hong Kong could go very badly for Xi, a leader who has tried to project an aura of resolve and near infallibility. Today Beijing trumpets that its 1.4 billion people stand united in their opposition to Hong Kong’s democracy movement. But that is a claim only sustainable in an environment of suffocating media control in China.