Jonathan Freedland explores the past behind the present. In the last of this long view of the future we ask when do civilizations & systems know that things cannot go on as they are. When do the rulers and the ruled sense the game is up? Historians Craig Clunas summon up the last days of the Ming Dynasty of the 17th Century, Maria Fusaro considers how the Venetian Republic registered its waning powers & end days in the 18th Century and Anthony Badger explores the existential crisis of America in 1933-would it survive as a democracy, could it be reformed & avoid collapse? Producer Mark Burman