It is a common mistake in going to war to begin at the wrong end, to act first and to wait for disaster to discuss the matter.
Whoever makes war through choice or ambition has the intention of making gains and keeping them, and of acting in such a way as to enrich his city and his country and not to make them poor. He must, then, both in the gaining and in the keeping, take care not to spend, but rather to do everything to the profit of the public.
Weigh the situation, then move.
Now the elements of the art of war are first, measurement of space; second, estimation of quantities,. third, calculations; fourth, comparisons, and fifth, chances of victory.
Quantities derive from measurement, figures from quantities, comparisons from figures, and victory from comparisons.
No one starts a war - or rather, no one in his senses ought to do so - without first being clear in his mind what he intends to achieve by that war and how he intends to conduct it.
He [the belligerent] would act on the principle of using no greater force, and setting himself no greater military aim, than would be sufficient for the achievement ofhis political purpose.
Of even greater influence on the decision to make peace is the consciousness of all the effort that has already been made and of the efforts yet to come. Since war is not an act of senseless passion but is controlled by its political object, the value of this object must determine the sacrifices to be made for it in magnitude and also in duration. Once the expenditure of effort exceeds the value of the political object, the object must be renounced and peace must follow.
To discover how much of our resources must be mobilized for war, we must first examine our own political aim and that of the enemy. We must gauge the strength and situation of the opposing state. We must gauge the character and abilities of its government and people and do the same in regard to our own. Finally, we must evaluate the political sympathies of other states and the effect the war may have on them. To assess these things in all their ramifications and diversity is plainly a colossal task. Rapid and correct appraisal of them clearly calls for the intuition of a genius; to master this complex mass by sheer methodological examination is obviously impossible. Bonaparte was quite right when he said that Newton himself would quail before the algebraic problems it could pose. The size and variety of factors to be weighed, and the uncertainty about the proper scale to use are bound to make it far more difficult to reach the right conclusion.