Augustine cites Cicero on the destruction of the Roman Republic due to the decline of traditional morality:
…the great leaders could not have founded, or could not have so long maintained such a great state with such a vast stretch of empire, had there not been that morality in the community; nor could the morality have done so, without the leadership of such men. Thus, before our own period, the traditional moral code produced outstanding men, and these excellent men preserved the code and the practices of their forebears. Whereas our age has received the commonwealth like a magnificent picture which has almost faded away with age, and it has not only omitted to restore it with the original colours; it has not even taken the trouble to preserve what one may call the general shape and the bare outlines. For what remains of that ancient morality which, according to the poet, supported the Roman state? We see that it has passed out of use into oblivion, so that far from being cultivated, it does not even enter our minds. And what about the men? The morality has passed away through lack of the men: and we are bound to be called to account for this disaster, and even, one may say, to defend ourselves on a capital charge. For we retain the name of a commonwealth, but we have lost the reality long ago: and this was not through any misfortune, but through our own misdemeanours. – City of God II.21, trans. Henry Bettenson, citing Cicero, De Republica 5.1
Are we really sure he’s talking about Rome, here?