With growing experience, all skillful commanders sought to profit by the power of the defensive, even when on the offensive.

For if we merely take what obviously appears the line of least resistance, its obviousness will appeal to the opponent also; and this line may no longer be that of least resistance. In studying the physical aspect, we must never lose sight of the psychological, and only when both are combined is the strategy truly an indirect approach, calculated to dislocate the opponent's balance.

To ensure attaining an objective, one should have alternate objectives. An attack that converges on one point should threaten, and be able to diverge against another. Only by this flexibility of aim can strategy be attuned to the uncertainty of war.

The only thing harder than getting a new idea into the military mind is to get an old one out.

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.

I used to think that the causes of war were predominantly economic. I came to think that they were more psychological. I am now coming to think that they are decisively "personal," arising from the defects and ambitions of those who have the power to influence the currents of nations.

It 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.