But that tailwind may have been squandered, because the Kirchners have yet to make the structural changes in industry, in the country s energy policy, in education, and elsewhere needed to free Argentina from extreme dependence on commodity prices.

With greater clarity in terms of Chinese and US policy, both economies should gain momentum. That will give developing countries (many of which face difficult domestic policy choices) a tailwind, while making the substantial challenges in Europe and Japan easier to address.

As Gordon notes, there have been long lasting productivity dividends associated with urbanization a trend that could continue for at least another decade in China. But there will come a time when this tailwind subsides and China begins to converge on the so called frontier of the advanced economies.

The pattern of flying geese is a useful metaphor to explain this idea. Beginning in the eighteenth century, the less developed West European and East Asian countries followed their more successful neighbors emulating a flying geese pattern, they benefited from the leaders tailwind as they first industrialized and then became advanced countries themselves.