Following the onset of the recession that followed the 2008 global financial crisis, China’s policymakers spent seven years replacing waning demand for their country’s net exports with a homegrown investment bubble, inflated by local governments’ aggressive land sales. And when the moment of reckoning came this summer, China’s leaders spent $200 billion of hard-earned foreign reserves to play King Canute trying to hold back the tide of a stock-market rout.