Is it too late to halt the slide towards all-out confrontation between China and the western democracies? An apparently conciliatory speech last week by Xi Jinping led some observers to suggest China’s president may want to mend fences. But a change of tone in Beijing will not cut much ice in Washington unless Xi’s aggressive policies change, too. Since coming to power in 2012, Xi has overseen a marked shift towards authoritarianism at home and...