The Decline and Fall of the Roman Empire

In his monumental study entitled The Decline and Fall of the Roman Empire, historian Edward Gibbon listed five reasons that the enormous empire collapsed:
1. The increase in divorce, undermining the institution of the family;
2. The imposition of higher taxes for bread and circuses;
3. The drive for pleasure, sports becoming more exciting and brutal;
4. The people lost their faith.
But the most important was the fifth reason:
5. The existence of an internal conspiracy, working to undermine the government from within, all the time that the government was proclaiming that Rome's enemy was external.
Gibbon reported that the conspiracy was building huge armaments for protection against both real and imaginary external enemies, all the while they were literally destroying the empire from within.
These causes have parallels in today's world as well.

The existence of an accepted external menace, then, is essential to social cohesiveness as well as to the acceptance of political authority. The menace must be believable, it must be of a magnitude consistent with the complexity of the society threatened, and it must appear, at least, to affect the inure society. 

The Unseen Hand