The lessons of 10,000 years of world history are clear, Turchin argues: when the equilibrium between ruling elites and the majority tips too far in favor of the elites, political instability is all but inevitable. Before the industrial era, the imbalance between labour and capital, signaled by growing economic inequality, was usually caused by excessive population growth.

For the past 250 or so years, it has been laissez-faire government, technological innovation, globalization and immigration that have tended to disrupt the balance. Whatever the cause, when income inequality surges the common people suffer, and prosperity flows disproportionately into the hands of the elites.

This vicious cycle is the wealth pump - the mechanism that causes both the relative impoverishment of most people and the increasingly desperate competition among elites. The wealth pump has been operating full blast for two generations in America and in many Western countries.

In historical terms, our current cycle of elite overproduction and popular immiseration is already far along the path to violent political rupture. Time will tell whether Peter Turchin's warning is heeded.