Imperial overstretch


Imperial overstretch, also known as Imperial overreach, is a hypothesis which suggests that an empire can extend itself beyond its ability to maintain or expand its military and economic commitments. Arguably, this was true of the Roman Empire, which was strong and effective in the first and early second centuries CE, despite a few setbacks but lost territories after that and could not keep the Saxons, Huns and other 'barbarians' out in the 4th and 5th centuries.
Clearly, this was true of the Napoleonic Empire, which made rapid gains by conquest in the first decade after Napoleon became dictator of France, but became over-extended militarily when it attempted to conquer Russia in 1812. Likewise the German Reich in 1942.
The idea was popularised by Yale University historian Paul Kennedy in his 1987 book The Rise and Fall of the Great Powers.

Criticism

Paul Kennedy's view has been criticised from many directions, including the postmodern historiographer Hayden White, economic historian Niall Ferguson and from Marxist writers such as Perry Anderson and Alex Callinicos.