Gibbon famously wrote that Christianity was partly responsible for the fall of the Roman Empire. By encouraging pacifism and other-worldliness, he argued, Christianity sapped Rome’s fighting spirit. Who knows? Correlation isn’t causation, after all, and anyway a Christian version of the empire survived another 1000 years in the east. But if the rise of Christianity explains Rome’s fall, what explains the apparent decline of the Pax Americana? Surely not the spread of Christian identity: the decline of American influence correlates with a decline in the percentage of Americans who identify as Christians. This week, Yale publishes a book that attempts to explain what’s going on, Why Empires Fall: Rome, America, and the Future of the West. The authors are historians Peter Heather (King’s College, London) and political economist John Rappley (Cambridge). Looks fascinating. Here’s the publisher’s description:

Over the last three centuries, the West rose to dominate the planet. Then, around the start of the new millennium, history took a dramatic turn. Faced with economic stagnation and internal political division, the West has found itself in rapid decline compared to the global periphery it had previously colonized. This is not the first time we have seen such a rise and fall: the Roman Empire followed a similar arc, from dizzying power to disintegration.

Historian Peter Heather and political economist John Rapley explore the uncanny parallels, and productive differences between ancient Rome and the modern West, moving beyond the tropes of invading barbarians and civilizational decay to unearth new lessons. From 399 to 1999, they argue, through the unfolding of parallel, underlying imperial life cycles, both empires sowed the seeds of their own destruction. Has the era of Western global domination indeed reached its end? Heather and Rapley contemplate what comes next.