2. A great moral and physical superiority, which justifies the adoption of a decisive method.
3. The want of impulsive force in the enemy as soon as he has arrived at the culminating point of his career.
When Frederick the Great invaded Bohemia, 1757, on converging lines, he had not in view to combine an attack in front with one on the strategic rear, at all events, this was by no means his principal object, as we shall more fully explain elsewhere, but in any case it is evident that there never could have been any question of a concentration of forces in Silesia or Saxony before the invasion, as he would thereby have sacrificed all the advantages of a surprise.
When the allies formed their plan for the second part of the campaign of 1813, looking to their great superiority in numbers, they might very well at that time entertain the idea of attacking Buonaparte’s right on the Elbe with their main force, and of thus shifting the theatre of war from the Oder to the Elbe. Their ill-success at Dresden is to be ascribed not to this general plan but to their faulty dispositions both strategic and tactical. They could have concentrated 220,000 men at Dresden against Buonaparte’s 130,000, a proportion of numbers eminently favourable (at Leipsic, at least, the proportion was as 285 : 157). It is true that Buonaparte had distributed his forces too evenly for the particular system of a defence upon one line (in Silesia 70,000 against 90,000, in the Mark—Brandenburg—70,000 against 110,000), but at all events it would have been difficult for him, without completely abandoning Silesia, to assemble on the Elbe a force which could have contended with the principal army of the allies in a decisive battle. The allies could also have easily called up the army of Wrede to the Maine, and employed it to try to cut Buonaparte off from the road to Mayence.
Lastly, in 1812, the Russians might have directed their army of Moldavia upon Volhynia and Lithuania in order to move it forward afterwards against the rear of the principal French army, because it was quite certain that Moscow must be the extreme point of the French line of operations. For any part of Russia beyond Moscow there was nothing to fear in that campaign, therefore the Russian main army had no cause to consider itself too weak.
This same scheme formed part of the disposition of the forces laid down in the first defensive plan proposed by General Phul, according to which the army of Barclay was to occupy the camp at Drissa, whilst that under Bragathion was to press forward against the rear of the main French army. But what a difference of circumstances in the two cases! In the first of them the French were three times as strong as the Russians; in the second, the Russians were decidedly superior. In the first, Buonaparte’s great army had in it an impulsive force which carried it to Moscow 80 miles beyond Drissa: in the second, it is unfit to make a day’s march beyond Moscow; in the first, the line of retreat on the Niemen did not exceed 30 miles: in the second it was 112. The same action against the enemy’s retreat therefore, which was so successful in the second case, would, in the first, have been the wildest folly.
As the action against the enemy’s line of retreat, if it is more than a demonstration, becomes a formal attack from the rear, there remains therefore still a good deal to be said on the subject, but it will come in more appropriately in the book upon the attack; we shall therefore break off here and content ourselves with having given the conditions under which this kind of reaction may take place.
Very commonly the design of causing the enemy to retreat by menacing his line of retreat, is understood to imply rather a mere demonstration than the actual execution of the threat. If it was necessary that every efficacious demonstration should be founded on the actual practicability of real action, which seems a matter of course at first sight, then it would accord with the same in all respects. But this is not the case: on the contrary, in the chapter on demonstrations we shall see that they are connected with conditions somewhat different, at all events in some respects, we therefore refer our readers to that chapter.
CHAPTER XXV.
Retreat into the Interior of the Country
We have considered the voluntary retreat into the heart of the country as a particular indirect form of defence through which it is expected the enemy will be destroyed, not so much by the sword as by exhaustion from his own efforts. In this case, therefore, a great battle is either not supposed, or it is assumed to take place when the enemy’s forces are considerably reduced.