Having a less extensive field of action than in the case of the cavalry on the flank, it is all the more necessary, if there is no chance of a charge, for it to act in the manner of a reserve. The cavalry must not shrink, when necessity demands, from employing its whole force in the fire fight, disregarding for this purpose its purely cavalry rôle, which may, perhaps, be resumed later. The first essential is that victory shall be won. To this end all available forces must co-operate. We will find a good example to follow in the battle of Fredericksburg and the manner in which Stuart threw the whole of his cavalry into the fight. The employment of cavalry in the War of Secession in North America, the study of which I have urgently recommended, can here again serve us as a guide to follow.
3. Pursuit and Retreat
In critical study of military history there is continual cause for complaint that after a victorious battle no effective pursuit, with a few brilliant exceptions, has ever taken place. These complaints are justified. It must, however, be conceded that a failure of the pursuit may be traced in most instances to the force of circumstances.
As the day of battle draws to a close and the decision has taken place, the victorious attacker has generally accomplished a long march to the battlefield and carried out an exceedingly exhausting attack. The troops have perhaps all been employed in the battle, down to the last reserve. Ammunition, food, and water are often lacking. It is therefore quite natural that the mere physical energy required for a pursuit is wanting. If, on the other hand, the defender is successful, it is generally against a superior enemy, or one that is thought to be superior. With the greatest expenditure of moral and physical force he has held his own. In the evening of the day of battle, when the attacks cease, he is still perhaps scarcely conscious of his victory, and still imagines that the enemy is endeavouring to turn his flank. He awaits renewed onslaughts, and will be fearful of imperilling his success by leaving the positions which he has maintained with such difficulty, in order, on his side, to take up the offensive. It is therefore but natural that a pursuit should at first remain in abeyance. If, however, it is not carried out at once, the favourable opportunity is generally lost forever.
The beaten defender, on the other hand, has often still a surplus of fresh troops. On the day of battle he will generally have had no exhausting marches to undertake. The battle has not imposed nearly such heavy physical demands upon him as upon the attacker. He has also been able to supply himself during the fight much better than the latter. To these factors of advantage must be added the instinct of self-preservation of the individual, which continually induces afresh the desire to escape from the grasp of the enemy. What can be more natural for the beaten defender after a lost battle than to march long distances, and thus successfully to evade pursuit, unless it be immediately undertaken? General von Goeben gave orders on the evening of the battle of St. Quentin that all troops must march five miles[42] the next day. But the French had already covered a similar distance during the night, and were no longer within reach.
The beaten attacker also may, after the battle, no longer have at his disposal sufficient physical force to carry out a further immediate march, but, as before the fight he was in superior force, or considered himself to be so, it will not be necessary for him to withdraw from the enemy as quickly as a beaten defender. The reason for this lies in the difficulty which exists for the latter of taking up the pursuit. The attacker can then utilise the time after the battle to secure himself in the terrain and to re-form his units. He falls back on his reserves of supply and ammunition. Unless he has suffered a destructive defeat, the pursuer will generally find him the next morning again in a condition to offer some resistance.
The factors of weakness, therefore, which allow but seldom of an effective pursuit have their origin in the nature of circumstances, and are exceedingly difficult to cope with.
Energy and activity sufficient to this end are only to be found in moments of the greatest moral excitement, under the influence of overpowering personalities, or under special conditions, such, for example, as resulted after the battle of Waterloo. In the future, however, we shall generally have to reckon that these factors of weakness will prevail and the pursuit fail unless it is prepared with conscious intention in good time, and initiated with energy.
Here will certainly be required careful leading, good tactical judgment, and rapid decision.