"The Art of War, in order to arrive at its aim (which is to impose its will upon the enemy), knows but one means, the destruction of the adversary's organised forces. So we arrive at the battle, the only argument of war, the only proper end that may be given to strategical operations, and we begin by establishing the fact that to accomplish the aim of war the battle cannot be purely defensive. The results of a defensive battle are exclusively negative; it may check the enemy in his march; it may prevent him from achieving his immediate aim; but it never leads to his destruction, and so is powerless to achieve the wished-for victory. Therefore, every defensive battle must terminate with an offensive action or there will be no result" (Marshal Foch).
CHARACTERISTICS OF THE BATTLE.—No two battles are precisely similar, but there are certain characteristics common to every battle.
In the first place, the issue is almost always uncertain, for events which no human sagacity could provide against may occur to defeat the wisest plans. The best chances, therefore, are on the side of the commander who is provided with sufficient means to achieve his object, who forms his plans with the greatest sagacity, and executes them with the greatest ability. Decisive success has followed the combinations of great commanders, and in the long run victory pays homage to knowledge of the principles which underlie the art of war. {25}
In the second place, the human factor always plays its part in battle. Troops lacking in discipline are liable to panic in face of a sudden disaster, and even the best troops are liable to become unsteady if their flank is gained.
In the third place, a comparatively small body of fresh troops thrown into action at the right moment against greater numbers, if the latter are exhausted by fighting, may achieve a success out of all proportion to their numbers. For this reason a prudent commander will endeavour to retain under his control some portion of his reserves, to be thrown in after his adversary has exhausted his own reserve power.
To be superior at the point of attack is the Art of Warfare in a nutshell, and for this reason attacks on separate points of a position must be properly synchronised to be effective. The unbeaten enemy will otherwise possess a mobile reserve with which to reinforce threatened points. The attacks must be so timed that he throws them in piecemeal or fails to reach the point mainly threatened.
McClellan's position with the Army of the Potomac on Malvern Hill (July 1, 1862) was a desperate position to attack in front, but it could have been turned on the right. The hill dominated the ground to the north, and also the road on which Lee's Army of Northern Virginia was approaching, and was crowned with numerous heavy guns, against which Lee's artillery was powerless. It was Lee's intention to open with an attack by a division, supported by two brigades, on the right of the position, and when this force was at grips with the Army of the Potomac, to assault the centre with a bayonet charge. About 5 p.m. the sound of cheering was heard near the right of the position, and mistaking this for the signal, General D. H. Hill launched the attack on the centre. The first line of defence was carried, but the Northern Army was unoccupied in the other parts of the line, and reinforcements quickly {26} beat off the attack with heavy loss. After this attack had failed, Magruder's division arrived in position and the attack on the right flank was delivered with similar results. Both attacks were carried out with superb courage, but partial blows of this nature are without the first elements of success, and McClellan's movements were not again molested.
PHASES OF THE BATTLE.—There are three principal phases of every battle. Information must be obtained by observation and by fighting; advantage must be taken of information so obtained to strike where the blow or blows will be most effective; success obtained by fighting must be developed until the enemy is annihilated.
Information and the Initiative.—Much work requires to be done in the air and on the land before the rival armies come face to face. Aircraft and the independent cavalry (advanced mounted troops and fast tanks detached from divisions for the purpose), endeavour to ascertain whether, and if so in what locality and in what strength, troops are being concentrated by the enemy. From information so obtained the Headquarters Staff are able to conjecture the intentions and aims of the enemy, and the extent to which their own intentions and aims have been perceived by the enemy. After the enemy is encountered this information is at the service of the Commander of the troops, but it will generally require to be supplemented by fighting. On each side the commander will be striving to obtain the initiative, to impose his will upon his opponent, for the commander who loses the initiative is compelled to conform to the plans and movements of his adversary, instead of bringing into operation plans and movements better suited to his own purposes. Each is scheming to obtain or retain the liberty of manoeuvre, in the same way as, in the days of sailing ships, a naval commander strove to get the "weather gauge" in every encounter.
The initiative won by the Strategy of one commander {27} is sometimes wrested from him by the Tactics of his adversary. This was exemplified at the Battle of Salamanca (July 22, 1812). Wellington, the generalissimo of the Anglo-Portuguese forces, had decided to withdraw behind the River Tormes to the stronghold Ciudad Rodrigo, and had dispatched his train to that centre. The French Commander (Marmont), in his eagerness to intercept Wellington's line of retreat, moved part of his force to the Heights of Miranda, thus threatening Wellington's right and rear, but leaving a gap of two miles between the detached force and his main army. Wellington noted the fresh disposition of Marmont's army through his telescope, and exclaiming, "That will do!" he abandoned all idea of the withdrawal which had been forced upon him by Marmont's previous manoeuvres, and hurled part of his force against the detached body (which was defeated before Marmont could send assistance) and at the same time barred the progress of the main army, which was forced to leave the field. Wellington afterwards declared, "I never saw an army receive such a beating." If the Spanish General in alliance with Wellington had not, contrary to the most explicit instructions, evacuated the Castle of Alba de Tormes (which commanded the fords over which the French retreated), "not one-third of Marmont's army would have escaped" (Napier).