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.

The higher level of grand strategy [is] that of conducting war with a far-sighted regard to the state of the peace that will follow.

In a campaign against more than one state or army, it is more fruitful to concentrate first against the weaker partner than to attempt the overthrow of the stronger in the belief that the latter's defeat will automatically involve the collapse of the others.

The military weapon is but one of the means that serve the purposes of war: one out of the assortment which grand strategy can employ.

For the spread and endurance of an idea the originator is dependent on the self-development of the receivers and transmitters.

In war, the chief incalculable is the human will.

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.