Though members of a Chinese paramilitary police force are massing on ground adjacent to Hong Kong, use of hard power to end the protests would be a serious mistake. The integration of Hong Kong is not a discrete exercise for China. Rather, it is the first test of China's ability to exert decisive influence with its neighbours. Other nations of Asia, Europe and Africa are unlikely to welcome Chinese outreach if they know that Beijing's only response to disagreement is violence.
There's also the internal question. China's tremendous economic growth in the 30 years since Tiananmen Square has created tens of millions of rich and middle-class individuals. Would the wealthy and worldly citizens of Shanghai, for example, acquiesce in the violent oppression of Hong Kong? Ditto Beijing, Guangzhou, Shenzhen and other newly rich cities. China's strategy to reabsorb capitalist Taiwan peacefully someday would suffer a terrible blow if the Hong Kong experiment were to fail.
No nation is ready for global power that can't amicably coexist with a wealthy city under its control. The extradition law was a massive blunder by a domestic tyrant and demands a skillful, soft-power solution.
Xi's finesse is also being tested in western China, where overreliance on hard power has created an archipelago of concentration camps housing more than 1 million Uighur men, women and children. China's oppression of this Muslim minority surely encouraged Indian Prime Minister Narendra Modi's government in revoking the special status of the nearby disputed territory of Kashmir and embarking on a Muslim oppression of his own.
It is difficult to see how an emboldened and unquiet India is anything but bad for China's long-term ambitions. The two mega-nations are natural rivals, but it is better to compete with a peaceful and law-abiding neighbour than with a reckless and belligerent one. A leader adept at soft power would set that example.
Finally, Xi faces a test regarding President Donald Trump.
Whatever one thinks of Trump's trade-war goals, his tactics appear to have left him at Xi's mercy. The Chinese people - 60 per cent of whom spend less than US$10 ($15.59) a day - are far more accustomed to economic pain than Trump's Americans, and they have no meaningful right to vote. So Xi can probably afford to absorb the economic pain necessary to push the trade war past Election Day. This would greatly increase the chance of a recession in 2020 and damage the American president's chance of reelection.
On the other hand, Xi also has the power to make a few token concessions that would allow Trump to claim victory in the trade war. Markets would give a hearty cheer; Trump would crown himself the China slayer. But Xi might gain four more years of severe disruption in the West.
The hard-power choice here is probably to stay the course on trade negotiations, spreading the pain unevenly and disproportionately on China's impoverished majority. In the People's Republic, it's always the people who suffer. Confronting a US president and potentially ending his career would ratify China's arrival at superpower status.
Yet Xi may stand to gain more from the soft-power play, graciously springing Trump from the trap he stepped in. Trump's reelection would gratify his supporters and demoralise everyone else, further depleting the soft power of the United States. It's shocking that a US president has given such juicy options to the Chinese leader. We'll learn how canny Xi is by the choice he makes.