While there are many causes for which a state goes to war, its fundamental object can be epitomized as that of ensuring the continuance of its policy - in face of the determination of the opposing state to pursue a contrary policy. In the human will lies the source and mainspring of conflict.
B. H. Liddell HartWhile the nominal strength of a country is represented by its numbers and resources, this muscular development is dependent on the state of its internal organs and nerve-system - upon its stability of control, morale, and supply.
B. H. Liddell HartThe more usual reason for adopting a strategy of limited aim is that of awaiting a change in the balance of force ... The essential condition of such a strategy is that the drain on him should be disproportionately greater than on oneself.
B. H. Liddell HartIt should be the aim of grand strategy to discover and pierce the Achilles' heel of the opposing government's power to make war. Strategy, in turn, should seek to penetrate a joint in the harness of the opposing forces. To apply one's strength where the opponent is strong weakens oneself disproportionately to the effect attained. To strike with strong effect, one must strike at weakness.
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 Hart