Campaigns of 1862 and 1863, illustrating the principles of strategy

Preface

Few years of military annals are so fertile in events as that which has just expired. Full of varied chances, the year 1862 ought to teach us a great lesson. It ought to remind us that ''The great principles of war cannot be violated with impunity." It may be interesting as well as useful to investigate the causes, both of the great disasters which have befallen our armies, and of the successes which they have achieved.

By passing in review the different operations, and by discussing them from a strictly military stand-point, we may so perceive the errors of the past campaign as to be able to avoid similar ones in the campaigns to come. These reasons have induced me to write a military review of the campaign of 1862, and even to discuss operations which will probably take place in 1863.

Presumptuous as it may appear to undertake such a task, I am encouraged to do so by the remarkable manner in which events coincided with a similar discussion

VI PREFACE.

I discussed in that work operations which were afterward made by our generals. I pointed out the correct line of defense against these operations, and showed the results. The Rebels adopted this defense ; the results were as I had shown they would be. The present work may therefore be considered as a kind of treatise on grand war, and as a sequel to my '' Summary of the Art of War."

I hope the reader will judge it with indulgence, and, while perusing it, take into consideration that my only sources of information were the reports published in our newspapers, and such maps as may be found in any library.

E. S.

January, 1868.

Contents

PAGE

Introduction 9

I. Principles of Strategy 10

I. Principles Of Strategy

In order to understand the following pages, it is necessary to give a short exposition of the principal maxims of strategy. These maxims are deduced from the modes of operation in the field adopted by the great captains of all ages ; they furnish the rules of action in offensive or defensive campaigns.

War has existed nearly since the creation of the world ; the history of every country commences with war and the feats of its heroes. The objects for which war is waged have been in all ages nearly always the same. The principles on which it is conducted have remained unchanged from the first, although, with the progress of civilization, the understanding of those principles becomes more general, and the manner of fighting different.

The most complete discussion of the principles of strategy is to be found in Gen. Jomini's works, especially in his "Art of War." This work, though a standard one of its kind, is intended only for the military student, and requires considerable knowledge of military history before reading it. This is the reason why, instead of referring simply to his work, I present the following compact and easily understood treatise, which, however, will also be found in substance in my ''Summary of the Art of War.^^

BASE OP OPERATION. 11

Three great principles may be laid down as belonging to the entire science of war. They are —

1. To concentrate all disposable forces, and to act with the whole of them against a part only of the enemy's forces.

2. To act against the weakest part of the enemy ; against his center if his forces be not united, and against his flank or rear, if they be concentrated. Also, to act against his communications without endangering our own.

3. Whatever plan of operations has been decided on, it should be executed with the utmost promptness, so that the object may be attained before the enemy can prevent it.

Simple as these three great maxims may appear, their application is nevertheless of the greatest difficulty. In fact, this application varies with every new tract of land upon which we enter ; with every different position of the enemy, with every variation in the disposition of his forces and of our own army. In all these cases the circumstances vary, but the principles upon which to act remain the same ; and it is in the right application of these maxims to circumstances that the qualities of a great commander are displayed.

Before going farther, let us give here a few definitions and explanations.

Base of Operation. — On opening a campaign we must have a line for tli£ concentration of our troops, whereon to place our depots and magazines, and from which to advance to execute our different plans. This line is called the base of operation. The choice of this line is of the utmost importance, for the result of a whole campaign may depend upon it. Let o & c <Z be the theater of war. Now if a c and a h belong to us, and 6 cZ be the sea, or the frontier of some great neutral power, the army of the enemy has but one line of retreat left, viz., c d. We may choose ah.ov ac for our base. In choosing a b, the enemy's army would always have its retreat to c d free ; but in choosing a c, we may advance from Fto F\ cut the army A from its communications, and force it into the corner 6, where it would be obliged to surrender. The campaign of 1806 may serve as an illustration : b d, m this case, represents the North Sea ; a b the Khine, a c the Maine, and c d the Elbe ; c d was the only retreat for the Prussian army A. The French army F advanced from F to F^, defeated the Prussian army A at

LINES OF OPERATION. 13

Jena, and threw it back on the North Sea, where the remnant of it surrendered.

Or if a 6 is our base, and -^^S- 2.

c d that of the enemy, we might advance from m to c ,.-'''''

without fear of being driven ^ --''' from our communications, while the enemy would even be endangered by advancing on the straight line m n, because we would always be able to retreat to a ; but the enemy having only a small

base, will expose his own communications as soon as he tries to act on ours.

Lines of Communication are called the lines or roads joining us with our base, or to another army co-operating with us on the same theater of war.

Lines of Operation. — If the choice of the base of operation is of importance, that of the line of operation is still more so. We call line of operation the main road or direction which is followed by the principal body of the army. If there is but one army on the same frontier, the line will be simple ; if there are two armies, there will be a double line of operation.

The interior line of operation is the line which two or more armies would follow, if attacked from different sides by different armies, but so that they would be enabled to unite before the various corps of the enemy could do so.

2*

1^^

d b

Fig. 4.

T

The way from a to &, in Fig. 3, would be the interior line ; the way from c to d, the exterior line.

We call the lines of two or more Fig. 3. ^ armies or army corps, starting from

distant points and meeting together in one, concentric lines. (See Fig. 4.) Divergent lines leave one point to arrive at two or three distant points. If leaving a, a b and a c are divergent lines ; if b and c, they are concentric ones.

If an army is placed between two hostile armies, so that it can defeat either of them before they are able to effect a junction, its position is called a central one.

Besides the definitions already given, we call strategic points and lines all such points and lines on the theater of war the occupation of which may be of importance during the war.

We call lines of defense all those lines which we choose for defense, or which by the natural configuration of the ground admits of an easy defense. It is evident that the line must be a strategic one — that is, it must be so situated that by its occupation we prevent the enemy attaining his object.

Each theater of war can be divided into the three zones — right, left, and center.

OFFENSIVE OPERATIONS. 15

As general maxims of strategy, we may enumerate the following ; —

1. To turn to the best advantage the respective directions of our base of operation and that of the enemy.

2. To choose the one of the three zones of the theater of war on which we can cause the greatest disasters to the enemy with the least risk to ourselves.

3. In order to well direct the lines of operation in defense as well as in attack, the interior lines are always to be adopted. In defense, these lines ought to be concentric; in attack, which is just the reverse, they ought to be divergent.

4. No. 3 implies that we ought to choose our lines so that we can always unite our divisions before the enemy can unite his, and that with our united force we ought to beat him in detail.

5. To act with the utmost activity and speed.

It remains to be shown how these rules are to be applied to offensive and to defensive operations.

Offensive Operations. — Whatever be the geographical configuration of the theater of war, it can be divided into three zones — right, left, and center — as we have already seen ; but a choice is to be made as to which of the three zones is to be the scene of operations.

Circumstances may be such that one, two, or even all three zones may be employed : in the first case, we should have a simple line ; in the two others, several lines of operation.

1st. If there is but one line, two cases may occur — either that the enemy occupies a very extended line, or that he holds a concentrated position. In the first case, the most advantageous point to act on is the center, which we should break with our whole force, and then defeat each of the wings separately.

In 1796 Napoleon, when opposed to Beaulieu, whose line was extended from Genoa to Ceva, broke through the center of the Austro- Sardinian army at Montenotte, with his entire force, and then defeated the two wings, one after the other, in the engagements of Milesimo, Dego, and Mondovi.

In 1809, when opposed to the Archduke Charles, whose 'army also formed a very extended line, he acted in a similar way, and defeated successively the Austrian forces in the battles of Abensberg, Landshut, Eckmiihl, and Ratisbon.

In the second case, if the enemy keep his forces concentrated, the manoeuvre against his center is rendered impossible, or at least disadvantageous, and we should then see if an attack on one of the other two zones does not present the chance of our acting at once on the enemy's communications, without endangering our own.

Figures 1 and 2 will show how this is possible. When once on the enemy's communications, we cut off his line of retreat ; to return to his base he is obliged to force his way with the bayonet; if he fails in this attempt and is defeated, he will be forced to surrender. Examples of such operations are to be found in the campaigns of 1800, 1805, and 1806. In 1805 Mack, with an Austrian army, near Ulm, was turned by Napoleon and obliged to capitulate. This result was obtained in consequence of the position and extension of the two bases of operation. Eig. 2 will explain this, by supposing that a b forms the base of the French, and

OFFENSIVE OPERATIONS. It

that they advance from a to n, and that they cut the Austrian army, which has advanced in the direction of w, from its base c d. The case of the campaign of 1806 is explained under the head of base of operation, illustrating the meaning of Fig. 1.

Should the enemy, however, maintain such a position that neither the manoeuvres against his center nor against his communications are possible, it will be necessary to resort to stratagems which shall induce him to make wrong movements, divide his troops, extend his lines, etc. For instance, we may^ give our whole army such a position, or we may, before the commencement of operations, place the several corps of our army in such a manner that they can act with the same facility against two or more points very distant from each other. The enemy is thus obliged to divide his force, and our first position must be chosen so that we may, by a few hidden and forced marches, unite our whole army on the decisive point; having carried which, we can then defeat the enemy in detail.

2d. If we form two lines of operation, we should follow divergent lines — that is, we should place our armies between those of the enemy, and transport our main body alternately from one army to the other. The enemy's armies beiog isolated, cannot unite, and must fall under the blows of our superior force.

The plan of the campaign of 1800, as devised by Napoleon, is the finest example of this that can be ofi'ered.

Melas, with a large army in Italy, had arrived at a short distance from the French frontier; Kray, with another army, threatened the Rhine. Moreau, near Basle, was to act against Kray, and the reserve army, disposed on the Swfss frontier, was to act in Italy. Napoleon's plan was for Moreau to pass through Switzerland, cross the Rhine at Shafifhausen, cut off Kray from his communications, and thereby destroy his army, while Napoleon himself crossed the Alps by the passes of the Great St. Bernard, Simplon, St. Gothard, and Spliigen, and arrived in the rear of Melas. Moreau did not entirely conform to Napoleon's plan; he crossed the Rhine near Basle, where he was already in possession of a iete-de-pont, and, therefore, the campaign in Germany was not so decisive as that in Italy. Melas found himself turned, and was obliged to fight at Marengo, front against Austria; he was defeated, and consequently compelled to enter into a convention with Napoleon, by which the latter obtained the western portion of Italy as far as the Mincio. The battle of Marengo, and indeed the whole of Napo*leon's manoeuvres, took place only after he had received a reinforcement of fifteen thousand men from Moreau.

Defensive Operations. — We may act on the offensive even though the war be a defensive one for us. This will always be the case when we are ready to take the field before the enemy can; or when his dispositions are faulty, his army corps dispersed, etc., or when our numerical superiority is very great. The initiative is always advantageous, and the defensive only should be taken in case of inferiority in strength.

The defense, as well as the offensive, can act on simple or on several lines of operation ; the plan of it is always more or less intimately connected with the coftfiguration of the ground than that of the attack. In the defense, the

DEFENSIVE OPERATIONS. 19

natural or artificial obstacles of the country should supply the deficiency of men, either in strategical or in tactical operations. When acting on simple lines, and opposed only to one army, but that one superior, our own army should retreat, availing itself of all the natural obstacles of the theater of the war, such as rivers, mountains, etc.; it should organize small bodies for acting in the rear of the advancing enemy to endanger his convoys, and force him to send large detachments to cover them.

In making those detachments, the invading army becomes smaller the farther it advances, while, on the other hand, the . defending army generally becomes s-tronger the nearer it approaches the center of its country. If by this the difi"erence in force is decreased, and the chances rendered more equal, the army for the defense should pass to a vigorous offensive, either by unexpectedly attacking the enemy, or by awaiting him in a well chosen and strongly fortified position.

The campaign of 1812 is a fine example of such a defense. Napoleon entered Russia with 450,000 men. The Russian army retreated, defending only the town of Smolensk. Owing to the many corps Napoleon was obliged to leave behind to cover his communications, and to the losses already sustained, he arrived at Borodino with only 132,000 men. The Russians awaited him there with lit, 000 men, iu a partly fortified position. What was impossible against an army of 450,000 men could be tried against one of 132,000.

When the enemy has chosen two lines of operation, we may be inclined to take but one line of operation, and bring our army info a central position between his armies, so as to fall with our whole force on the first of his corps that presents itself, and then defeat the other. At the siege of Mantua, in 1196, Napoleon, being informed that Wurmser, who had advanced from the Tyrol against him, had divided his forces and was descending one bank of the Lake of Garda with his main body, while Quasdanowitch was descending the other, raised the siege of Mantua, advanced and stationed himself at one end of the lake, thereby gaining a central position, and, separating Wurmser from Quasdanowitch, the latter was defeated at Lonato and the former at Castiglione.

When obliged to form several lines of operation, we should arrange them inj;he following manner : —

If, for instance, 100,000 men are to resist an invading army of 150,000, divided into three armies of 50,000 each, we should divide our force also. We form three corps of observation, each numbering 15,000 men. We keep the remaining 55,000 in reserve, and transport them successively, by interior lines and forced marches, to the three army corps, and form every time a large army of t0,000 men, who should defeat the 50,000 opposed to them. The two remaining corps of observation, if pressed by their opponents, retreat, defending every inch of ground, but refusing open battle, till they are in turn reinforced by the reserve. In those cases the defense loses ground, but soon regains it.

If the enemy has formed double lines of operation very distant from each other, we should also form two lines, and retreat on concentric ones ; when we arrive at such points that our armies are only a few days' march distant from each other, we should leave a corps of observation before one of the enemy's armies, in order to mask our movements, and,

DEFENSIVE OPERATIONS. 21

with our main body, reach by forced marches our other army, unite with it, and defeat the enemy by our superiority; we then return to the first army, the fate of which will not remain long undecided.

In IT 96 the Archduke Charles, in Germany, defeated the armies of Jourdan and Moreau by retreating in concentric lines from the Rhine to the Bohemian frontier, where he united part of his two armies ; he first defeated Jourdan at Amberg and Wurzburg, and then Moreau at Emmendingen and Schlingen.

During the war of 1'758-1'762, Frederick the Great was attacked by a Russian, Austrian, and German imperial army. He resisted those three armies by disposing his own on interior lines. He always transported the mass of his troops to the endangered point by means of those interior lines, and defeated the different hostile armies one after the other.

In the years 1813 and 1814 Napoleon, in his defense, likewise acted on interior lines.

These different rules have reference only to the movements and operations of one or more armies when once in the field, but they do not give the great ensemble of a war, nor do they reflect any light on the manner in which wars of a different character are to be conducted. The entire plan of a campaign would be different if the war were a civil one, a religious one, a distant conquest, or an invasion. There is but little resemblance between the campaigns of 1806 and those of the Peninsular war, though both were wars of conquest. The configuration of the theater of war, the character of the people, their government, and political circumstances being different, other means and plans became necessary. Wars of conquest and occupation being those which at the present moment interest us most, we will devote a few pages to them, and see how they have been carried on at different times by great captains.

Wars of Conquest, or Great Invasions. — The manner of making war, or even of conducting -great invasions, has passed through various stages in the course of time.

Most of the wars recorded in ancient history were wars of conquest, in which entire populations were launched against others. Yery early, however, we find the commencement of military organization, and even standing armies. By-and-by more and more complete systems were introduced. In the classic times of Greece, those of Philip of Macedon, and of his great son, Alexander, in the times when the Roman eagle began to spread its powerful wings over the then known world, the art of war attained to a perfection which has been surpassed only in modern times ; and even the great masters of the art in later ages sought for wisdom and instruction in the deeds of the illustrious captains of antiquity.

The degeneracy of the Roman empire, the immense emigration of uncivilized hordes, the overthrow of Roman civilization, soon brought the art of war back to its childhood. In the time of the Crusades it is distinguished principally by the employment of large masses of combatants and brute force, which sometimes attains success, though void of art or skill.

All the great States of Europe, held by kings or emperors, were divided into a number of principalities, large or small, governed by petty chieftains, on whose good-will the chief rulers were more or less dependent. The consequence was, that all the governments of Europe were so much occupied in preserving internal order, that great invasions became almost impossible.

The times of Charles Y., Francis II., and Henry TV. revived the art of war, and we see great captains appearing on the stage ; but the political systems and circumstances of Europe did not change. In the times of Louis XIV. and Louis XY. we find wars, even by great captains, conducted in a slow and methodical manner, whence it was called *' methodic warfare." Armies at that time lived in tents, camped, had vast magazines around and near them, and could not exist without an immense bakery close to their heels.

This was the state of affairs at the commencement of the French Revolution ; but here the revolution made itself felt also. Immense armies being created, for which scarcely the necessary armament could be found, still less tents, camp equipage, and provision trains, it became necessary to quarter these armies in the towns and villages, in order to shelter and nourish them, and subsist them on the inhabitants. Movement was not only rendered easier by this system, but became a necessity, as no district could nourish for any length of time so great an accumulation of men. Consequently methodic warfare changed at once to rapid, daring marches, and manoeuvres on a grand scale. The old indispensable bakery gave way to the famous Roman maxim^ "War must nourish war."

The adoption of this great principle changed, as by magic, the entire system of warfare. Armies which had hitherto marched only five or six miles a day, now marched twenty or twenty-five. Where small operations, sueli as the taking of a fortress, or the conquest of a province, had satisfied the ambition of a general, we now see armies made to traverse hundreds of miles, and push right into the heart of an enemy's country.

Campaigns became more extended and more decisive. In a word, the reins were loosed, and intelligence, courage, enterprise, youth, and vigor were launched, without restraint, against the enemy. The system of quartering or living on the inhabitants of the land forms the basis of all great wars of conquest or invasion ; unless it be adopted, it is impossible to conquer an extensive country possessing large and organized armies.

Let us draw a comparison between the efficiency of two armies — the one acting according to the principles of methodic warfare, and being furnished continually from its base of supply and its magazines, the other acting according to the principle, "War must nourish war."

In the first case, provisions for several days must always be carried with the army ; immense supply trains have to follow it ; bad roads — which would, however, have sufficed for the passage of troops — become impassable, in consequence of the transit of the immense number of heavilyladen wagons. Everywhere there is stoppage in the advance and starting of troops, obstruction of roads, delay, and disorder. As soon as the provisions in the wagons are consumed, or nearly so, the army halts. With immense trouble and cost, a fresh supply of provisions is obtained after a number of days ; the army starts anew, but only to come to another halt as soon as its wagons are emptied again. But, then, another difficulty arises ; the army is already so far from its base that the supply by wagons becomes impossible ; the number of days the wagons require to be en route is to© great ; and in the mean time the army runs the risk of perishing from hunger. The consequence is, that an operation, whatever may be its strategic advantages, cannot be carried out, if it does not offer extraordinary means of communication with the base of supply ; and it follows that, instead of choosing the most advantageous strategic lines as lines of operation, the most comfortable and convenient lines of communication are selected as the principal strategic direction to be given to the armies. In other words, the quartermaster and the commissary are in reality the commanders. The army cannot march where they forbid, nor can it move until they are ready or want to be so.

It is scarcely necessary to remark that, in consequence of the slow marching and the frequent halts in order to maintain the supply of provisions, the enemy gains ample time to prevent the success of any plan of operation, not to mention the inducement which such large wagon trains offer for cavalry raids in the rear of the army. Do away with this system of feeding the troops, and movement will become a necessity ; the most advantageous strategic lines of operation can be chosen ; there is no stoppage, except by the enemy ; but this resistance is, under such circumstances, such as a general would desire. In other words, all that is impossible when following the old system, becomes possible with the new. Where two men can plant their feet, an army can

3* marcli ; and instead of months of operations, the campaign will take only as many weeks, or perhaps days.

I do not wish to advocate here a system of great and legally-organized robbery, which takes from the countryman all he has without any indemnification. I advocate only a reasonable and well-organized system of requisition, paying liberally for all it obtains, but furnishing the army with all the principal provisions from the country through which it passes. The greater the distance an army marches in one day, the more plentifully it may be supplied.

All wars of invasion or conquest, from the earliest times down to the most modern — from the Romans to Napoleon — were based upon, and rendered possible by, this principle alone. Successful wars of conquest are therefore synonymous with rapid and energetic operations. Let us pass in review some of the principal.

Conquering a country, means successfully fighting its defenders; subduing a country, means occupying it. Fighting means concentration, occupying means division of forces. Here is evidently the difficulty of wars of conquest. As long as only the army of the invaded country takes part in the struggle, an occupation is scarcely necessary till this army is really destroyed ; bat the moment the war against the invader becomes national, and the population takes part in it, matters become different and more difficult. In this latter case, the operating or field army should not be reduced by detachments, but the troops necessary for the occupation should be sent from the base of operations.

Three systems have been principally employed for the conquest of a country. The first, is to march several armies from the circumference into the center of a country ; the second, is to conquer it by subduing and occupying one province after another; the third, is by marching one large force, on a single line of operation, right into the center of a country, and when arrived there, spreading, it out in all directions, like a fan, forming interior lines, dividing thereby the enemy, and forcing him to act on exterior lines. It is the very inverse of the first system.

The first system, viz., that of acting with several armies from the circumference against the center of a country, has been spoken of above in treating of offensive and defensive operations. We have seen that, though each of the invading armies may be stronger than the one opposed to it, the defense has the advantage ; b<!tause it acts on interior lines, and can unite its forces before the invading armies can unite theirs on the exterior lines, on which they are obliged to act.