of operations which must be traversed, the more it will be weakened (by marches and garrisons); the army on the defensive continues to keep up its connection with everything, that is, it enjoys the support of its fortresses, is not weakened in any way, and is near to its sources of supply.
The support of the population as a fifth principle is not realised in every defence, for a defensive campaign may be carried on in the enemy’s country, but still this principle is only derived from the idea of the defensive, and applies to it in the majority of cases. Besides by this is meant chiefly, although not exclusively, the effect of calling out the last Reserves, and even of a national armament, the result of which is that all friction is diminished, and that all resources are sooner forthcoming and flow in more abundantly.
The campaign of 1812, gives as it were in a magnifying glass a very clear illustration of the effect of the means specified under principles 3 and 4. 500,000 men passed the Niemen, 120,000 fought at Borodino, and much fewer arrived at Moscow.