In any problem where an opposing force exists and cannot be regulated, one must foresee and provide for alternative courses. Adaptability is the law which governs survival in war as in life ... To be practical, any plan must take account of the enemy's power to frustrate it; the best chance of overcoming such obstruction is to have a plan that can be easily varied to fit the circumstances met.
B. H. Liddell HartThis high proportion of history's decisive campaigns, the significance of which is enhanced by the comparative rarity of the direct approach, enforces the conclusion that the indirect is by far the most hopeful and economic form of strategy.
B. H. Liddell HartIt is folly to imagine that the aggressive types, whether individuals or nations, can be bought off ... since the payment of danegeld stimulates a demand for more danegeld. But they can be curbed. Their very belief in force makes them more susceptible to the deterrent effect of a formidable opposing force.
B. H. Liddell HartIn war the chief incalculable is the human will, which manifests itself in resistance, which in turn lies in the province of tactics. Strategy has not to overcome resistance, except from nature. Its purpose is to diminish the possibility of resistance, and it seeks to fulfil this purpose by exploiting the elements of movement and surprise.
B. H. Liddell HartThe only thing harder than getting a new idea into the military mind is to get an old one out.
B. H. Liddell HartIf you find your opponent in a strong position costly to force, you should leave him a line of retreat as the quickest way of loosening his resistance. It should, equally, be a principle of policy, especially in war, to provide your opponent with a ladder by which he can climb down.
B. H. Liddell Hart