the key role in such trend reversals is played by long periods of persistent political instability. Eventually the elites become alarmed at incessant violence and disorder. They realize that they need to pull together, suppress their internal rivalries and switch to a more cooperative way of governing. Such a shift in the social mood is observed repeatedly in history (Turchin and Nefedov 2009)—towards the end of Roman civil wars (first century BC), following the English Wars of the Roses (1455–85), and after the Fronde (1648–53).
