To follow exclusively either of these systems would be equally absurd.

The true science of war consists in choosing a just medium between the two extremes.

The wars of Napoleon demonstrated the great truth, that distance can protect no country from invasion, but that a state, to be secure, must have a good system of fortresses, and a good system of military reserves and military institutions." In all military operations _time_ is of vast importance.

If a single division of an army can be retarded for a few hours only, it not unfrequently decides the fate of the campaign.

Had the approach of Blucher been delayed for a few hours, Napoleon must have been victorious at the battle of Waterloo.