the end of civilization as we know it

1 the complete collapse of ordered society.

2 used to indicate that someone is being alarmist or is overreacting to a trivial inconvenience or blunder as if it were enormously significant and catastrophic.

☞ This expression is supposedly a cinematic cliché, and was actually used in the film Citizen Kane (1941): 'a project which would mean the end of civilization as we know it'.

2010Guardian For Labour to stagger on for another term would be good neither for the country nor for the party … Some Labour politicians privately acknowledge this … But publicly, they continue to insist that a victory for anyone else will be the end of civilisation as we know it.