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 ClausewitzEverything in war is very simple, but the simplest thing is difficult. The difficulties accumulate and end by producing a kind of friction that is inconceivable unless one has experienced war. ... Countless minor incidents - the kind you can never really foresee - combine to lower the general level of performance, so that one always falls short of the intended goal.
Carl von ClausewitzIn war, while everything is simple, even the simplest thing is difficult. Difficulties accumulate and produce frictions which no one can comprehend who has not seen war.
Carl von Clausewitz