This essay was written in response to Gideon Rachman’s invitation to readers to sit his ‘2066 history exam’. Of 170 entries, the FT is publishing the best five (see panel for the others). This piece addresses the question: Why did the “end of history” only last for 20 years?

The most powerful foreign policy instrument of the 1990s and 2000s was not a weapon or a diplomatic alliance. It was an idea. Like all powerful ideas, this one was simple: to achieve economic success, nations would liberalise and become more responsible members of an international community. And it came to pass. For 20 years, the world converged on a single model of liberal order with unprecedented prosperity and great power co-operation.

The great historical puzzle of the 21st century is why the world’s great powers simultaneously, and almost gleefully, tore this order apart and ushered in a new age of rivalry, protectionism and limited war, in which they were all much worse off. Why did the end of history — as Francis Fukuyama, then a 37-year-old researcher at Rand Corporation, termed it — come to an end?