The author is Niccolò Machiavelli.
(Discourses on Livy, Book III, ch. 41. Translated by Julia Conaway Bondanella and Peter Bondanella for Oxford World's Classics.)
Here it is with little more context:
This approach [taken by Rome after a humiliating defeat] deserves to be noted and imitated by any citizen who finds himself giving advice to his native city, because where the ultimate decision concerning the safety of one's country is to be taken, no consideration of what is just or unjust, merciful or cruel, praiseworthy or shameful, should be permitted; on the contrary, putting aside every other reservation, one should follow in its entirety the policy that saves its life and preserves its liberty. This approach is imitated in word and deed by the French when they defend the majesty of their king and the power of their kingdom; for this reason, they hear no voice with more impatience than one which declares: 'This policy is disgraceful for the king'; for they say that their king cannot suffer shame in any of his decisions, either in good or in adverse fortune, because if he wins or if he loses, everyone agrees it is entirely a king's affair.
Machiavelli's name is usually associated with a devious sort of autocracy, but he actually preferred a republican (albeit imperial) form of government -- especially after the Medici declined to hire him.
Ah, Machiavelli. Such wonderful notions on how to run a state... as long as you don't have to be a simple citizen of said state. Of course, that's kind of the point.