“IN AN UNCERTAIN world, China is the biggest certainty.” So proclaimed a Chinese spokesman in December. Amid a war in Europe, turmoil in the Middle East and America’s rewriting of the geopolitical order, some in the West may be inclined to agree. As The Economist went to press, Britain’s prime minister, Sir Keir Starmer, was visiting China’s president, Xi Jinping, the latest among a series of Western leaders who have headed to Beijing in search of deals and dependability. Yet in recent days politics in China has proved anything but certain. On January 24th the defence ministry said that the...