3. With his whole force to attack the enemy in flank.
4. To operate against his communications.
5. By a counter attack on his theatre of war, to do exactly what the enemy has done in passing by us.
We introduce this last measure, because it is possible to imagine a case in which it may be efficacious; but as it is in contradiction to the object of the defence, that is, the grounds on which that form has been chosen, therefore it can only be regarded as an abnormity, which can only take place because the enemy has made some great mistake, or because there are other special features in a particular case.
Operating against the enemy’s communications implies that our own are superior, which is also one of the fundamental requisites of a good defensive position. But although on that ground this action may promise the defender a certain amount of advantage, still, in the defence of a theatre of war, it is seldom an operation suited to lead to a decision, which we have supposed to be the object of the campaign.
The dimensions of a single theatre of war are seldom so large that the line of communications is exposed to much danger by their length, and even if they were in danger, still the time which the assailant requires for the execution of his blow is usually too short for his progress to be arrested by the slow effects of the action against his communications.
Therefore this means (that is the action against the communications) will prove quite inefficacious in most cases against an enemy determined upon a decision, and also in case the defender seeks such a solution.
The object of the three other means which remain for the defender, is a direct decision—a meeting of centre of force with centre of force; they correspond better, therefore, with the thing required. But we shall at once say that we decidedly prefer the third to the other two, and without quite rejecting the latter, we hold the former to be in the majority of cases the true means of defence.
In a position where our forces are divided, there is always a danger of getting involved in a war of posts, from which, if our adversary is resolute, can follow, under the best of circumstances, only a relative defence on a large scale, never a decision such as we desire; and even if by superior tact we should be able to avoid this mistake, still, by the preliminary resistance being with divided forces, the first shock is sensibly weakened, and we can never be sure that the advanced corps first engaged will not suffer disproportionate losses. To this is to be added that the resistance of this corps which usually ends in its falling back on the main body, appears to the troops in the light of a lost combat, or miscarriage of plans, and the moral force suffers accordingly.
The second means, that of placing our whole force in front of the enemy, in whichever direction he may bend his march, involves a risk of our arriving too late, and thus between two measures, falling short of both. Besides this, a defensive battle requires coolness and consideration, a knowledge, indeed intimate knowledge of the country, which cannot be expected in a hasty oblique movement to a flank. Lastly, positions suitable for a good defensive battle-field are too rarely to be met with to reckon upon them at every point of every road.