Timothy Garton Ash is a historian, political writer and Guardian columnist. His personal website is www.timothygartonash.com.

Amid the plethora of conspiracy theories about 9/11, one I have not yet seen is that Osama bin Laden was a Chinese agent. Yet objectively, comrades – as communists used to say – one could argue that China has been the greatest beneficiary of America's decade-long reaction to those Islamist stabs at her heart.

Put it this way: When the anniversary articles come to be written on 11 September 2031, will commentators look back on a 30 years war against Islamist terrorism, comparable to the cold war, as the defining feature of world politics since 2001? I think not. They will most likely see this longer period as being defined by the historic power shift from west to east, with a much more powerful China and a less powerful United States, a stronger India and a weaker European Union.

As the Stanford historian Ian Morris points out in his mind-stretching book Why the West Rules – for Now, this geopolitical shift will occur within the larger frame of an unprecedented rate of technological advance, on the bright side, and an unprecedented array of global challenges, on the dark side.

Of course, this is only historically informed guesswork. But if things develop in anything like this direction (or in another direction unrelated to Islam) then the post-9/11 decade in American foreign policy will look like a detour – a massive, consequential detour, to be sure – rather than history's main road...