The shared understanding that is society, is founded upon a set of shared beliefs about right and wrong. This is the sanity of the society, which is expressed and maintained by tradition.
Hence, the moment most citizens no longer revere tradition, but revere themselves and their opinions, is the moment communal understanding starts to lose its sanity. And the moment this collapse begins is when a society violently replaces the traditional rule of a monarch with popular rule. This is why Arnold Toynbee noted in "A study Of History", that the decline of every civilisation begins with a class war that displaces the traditional rule of a monarch.
Then the society stops being "One nation under God" but starts to become a rabble. That is, it starts to lose wealth, order and the ability to defend itself. Thus, growing ever poorer and feeble until it is finally eradicated by its enemies.
And the only way an elected government can react to this increasing collapse, is to make it a crime to point out the obvious. Thereby further paralyzing society's feeble mind with tyranny.