As Mr Xi has accumulated power, he has made it clear that he will not tolerate Western-style democracy. Yet suppressing popular demands produces temporary stability at the cost of occasional devastating upheavals. China needs to find a way of allowing its citizens to shape their governance without resorting to protests that risk turning into a struggle for the nation’s soul. Hong Kong, with its history of free expression and semi-detached relationship to the mainland, is an ideal place for that experiment to begin. If Mr Xi were to grasp the chance, he could do more for his country than all the emperors and party chiefs who have struggled to maintain stability in that vast and violent country before him.