Asia takes the long view. I once sat in on a discussion in Beijing about the future of American power. The examination question set at the China Institutes of Contemporary International Relations asked where the US would be in 2050. In a country usually shy of displaying differences within the ruling elites, it generated a strikingly animated debate.

On one side were those who were convinced that the ingredients of US power — geography, demography, resources, economic vitality, technological prowess and military might among them — would endure. On the other were those who said the US would go the way of great powers through history, laid low by political stasis, cultural decadence and economic decline. No one took a vote, but the first group had the better of the argument.

This debate took place before the global financial crash and the Beijing Olympics. My guess is that had the discussion been repeated a few years later, the pessimists (or were they optimists?) would have carried the day. The story I have heard over and again in east Asia these past few years has been one of impending American retreat. Allies as well as adversaries have doubted the US would stay the course.