Mid-July should have been a moment of quiet satisfaction in Beijing. Fresh data showed China’s favourability surpassing that of the United States in 25 of 37 nations surveyed by Pew Research Centre, including key European countries. Domestically, the second-quarter gross domestic product growth of 4.3 per cent, while softer than the first financial quarter, kept the annual target within reach. The logic was simple: with the US distracted by Donald Trump’s erratic trade wars and isolationist...