If the enemy is to be coerced, you must put him in a situation that is even more unpleasant than the sacrifice you call on him to make. The hardships of the situation must not be merely transient - at least not in appearance. Otherwise, the enemy would not give in, but would wait for things to improve.
Carl von ClausewitzA general in time of war is constantly bombarded by reports both true and false; by errors arising from fear or negligence or hastiness; by disobedience born of right or wrong interpretations, of ill will; of a proper or mistaken sense of duty; of laziness; or of exhaustion; and by accident that nobody could have foreseen. In short, he is exposed to countless impressions, most of them disturbing, few of them encouraging. ... If a man were to yield to these pressures, he would never complete an operation.
Carl von ClausewitzIn short, absolute, so-called mathematical, factors never find a firm basis in military calculations. From the very start, there is an interplay of possibilities, probabilities, good luck and bad, that weaves its way throughout the length and breadth of the tapestry. In the whole range of human activities, war most closely resembles a game of cards.
Carl von Clausewitz