The problems with China's economic growth pattern have become well known in recent years, with the Chinese stock market's recent free-fall bringing them into sharper focus. But discussions of the Chinese economy's imbalances and vulnerabilities tend to neglect some of the more positive elements of its structural evolution, particularly the government's track record of prompt corrective intervention, and the substantial state balance sheet that can be deployed, if necessary.

In this regard, however, the stock-market bubble that developed in the first half of the year should be viewed as an exception. Not only did Chinese regulators enable the bubble's growth by allowing retail investors — many of them newcomers to the market — to engage in margin trading (using borrowed money); the policy response to the market correction that began in late June has also been highly problematic.

Given past experiences with such bubbles, these policy mistakes are puzzling. I was in Beijing in the fall of 2007, when the Shanghai Composite Index skyrocketed to almost 6,000 (the recent peak was just over 5,000), owing partly to the participation of relatively inexperienced retail investors.