When law has become in a great measure impotent, when the most perfect innocence cannot alone insure safety, regard to self-defence obliges the greater part of men to have recourse to dexterity, to address, and to apparent accommodation to whatever happens to be, at the moment, the prevailing party.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“He exemplifies it by the characters of Homer’s Ulysses, of the Athenian Themistocles, of the Spartan Lysander, and of the Roman Marcus Crassus.7 This character of dark and deep dissimulation occurs most commonly in times of great public disorder; amidst the violence of faction and civil war. When law has become in a great measure impotent, when the most perfect innocence cannot alone insure safety, regard to self-defence obliges the greater part of men to have recourse to dexterity, to address, and to apparent accommodation to whatever happens to be, at the moment, the prevailing party. This false character, too, is frequently accompanied with the coolest and most determined courage. The proper exercise of it imposes that courage, as death is commonly the certain consequence of detection.” source