In the use of force, one simplifies the situation by assuming that the evil to be overcome is clear-cut, definite, and irreversible. Hence there remains but one thing: to eliminate it. Any dialogue with the sinner, any question of the irreversibility of his act, only means faltering and failure. Failure to eliminate evil is itself a defeat. Anything that even remotely risks such defeat is in itself capitulation to evil. The irreversibility of evil then reaches out to contaminate even the tolerant thought of the hesitant crusader who, momentarily, doubts the total evil of the enemy he is about to eliminate. P. 21
Thomas Merton