Now it confessedly lies in the nature of things, that on account of the greater spaces in strategy, the enveloping attack, or the attack from several sides, as a rule is only possible for the side which has the initiative, that is the offensive, and that the defensive is not in a condition, as he is in tactics, in the course of the action, to turn the tables on the enemy by surrounding him, because he has it not in his power either to draw up his forces with the necessary depth relatively, or to conceal them sufficiently: but then, of what use is the facility of enveloping to the offensive, if its advantages are not forthcoming? We could not therefore bring forward the enveloping attack in strategy as a principle of victory in general, if its influence on the lines of communication did not come into consideration. But this factor is seldom great at the first moment, when attack and defence first meet, and while they are still opposed to each other in their original position; it only becomes great as a campaign advances, when the offensive in the enemy’s country is by degrees brought into the condition of defensive; then the lines of communication of this new party acting on the defensive, become weak, and the party originally on the defensive, in assuming the offensive can derive advantage from this weakness. But who does not see that this casual superiority of the attack is not to be carried to the credit of the offensive in general, for it is in reality created out of the superior relations of the defensive. The fourth principle, the _Assistance of the Theatre of War_, is naturally an advantage on the side of the defensive. If the attacking army opens the campaign, it breaks away from its own theatre, and is thus weakened, that is, it leaves fortresses and depôts of all kinds behind it. The greater the sphere 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.