The Influence of Sea Power upon History. Alfred Thayer Mahan
for to effect it the ship must be carried to a single point of the field of action, whereas projectile weapons may be used from many points of a wide area.
The relative positions of two sailing-ships, or fleets, with reference to the direction of the wind involved most important tactical questions, and were perhaps the chief care of the seamen of that age. To a superficial glance it may appear that since this has become a matter of such indifference to the steamer, no analogies to it are to be found in present conditions, and the lessons of history in this respect are valueless. A more careful consideration of the distinguishing characteristics of the lee and the weather "gage,"3 directed to their essential features and disregarding secondary details, will show that this is a mistake. The distinguishing feature of the weather-gage was that it conferred the power of giving or refusing battle at will, which in turn carries the usual advantage of an offensive attitude in the choice of the method of attack. This advantage was accompanied by certain drawbacks, such as irregularity introduced into the order, exposure to raking or enfilading cannonade, and the sacrifice of part or all of the artillery-fire of the assailant,--all which were incurred in approaching the enemy. The ship, or fleet, with the lee-gage could not attack; if it did not wish to retreat, its action was confined to the defensive, and to receiving battle on the enemy's terms. This disadvantage was compensated by the comparative ease of maintaining the order of battle undisturbed, and by a sustained artillery-fire to which the enemy for a time was unable to reply. Historically, these favorable and unfavorable characteristics have their counterpart and analogy in the offensive and defensive operations of all ages. The offence undertakes certain risks and disadvantages in order to reach and destroy the enemy; the defence, so long as it remains such, refuses the risks of advance, holds on to a careful, well-ordered position, and avails itself of the exposure to which the assailant submits himself. These radical differences between the weather and the lee gage were so clearly recognized, through the cloud of lesser details accompanying them, that the former was ordinarily chosen by the English, because their steady policy was to assail and destroy their enemy; whereas the French sought the lee-gage, because by so doing they were usually able to cripple the enemy as he approached, and thus evade decisive encounters and preserve their ships. The French, with rare exceptions, subordinated the action of the navy to other military considerations, grudged the money spent upon it, and therefore sought to economize their fleet by assuming a defensive position and limiting its efforts to the repelling of assaults. For this course the lee-gage, skilfully used, was admirably adapted so long as an enemy displayed more courage than conduct; but when Rodney showed an intention to use the advantage of the wind, not merely to attack, but to make a formidable concentration on a part of the enemy's line, his wary opponent, De Guichen, changed his tactics. In the first of their three actions the Frenchman took the lee. gage; but after recognizing Rodney's purpose he manoeuvred for the advantage of the wind, not to attack, but to refuse action except on his own terms. The power to assume the offensive, or to refuse battle, rests no longer with the wind, but with the party which has the greater speed; which in a fleet will depend not only upon the speed of the individual ships, but also upon their tactical uniformity of action. Henceforth the ships which have the greatest speed will have the weather-gage.
It is not therefore a vain expectation, as many think, to look for useful lessons in the history of sailing-ships as well as in that of galleys. Both have their points of resemblance to the modern ship; both have also points of essential difference, which make it impossible to cite their experiences or modes of action as tactical _precedents_ to be followed. But a precedent is different from and less valuable than a principle. The former may be originally faulty, or may cease to apply through change of circumstances; the latter has its root in the essential nature of things, and, however various its application as conditions change, remains a standard to which action must conform to attain success. War has such principles; their existence is detected by the study of the past, which reveals them in successes and in failures, the same from age to age. Conditions and weapons change; but to cope with the one or successfully wield the others, respect must be had to these constant teachings of history in the tactics of the battlefield, or in those wider operations of war which are comprised under the name of strategy.
It is however in these wider operations, which embrace a whole theatre of war, and in a maritime contest may cover a large portion of the globe, that the teachings of history have a more evident and permanent value, because the conditions remain more permanent. The theatre of war may be larger or smaller, its difficulties more or less pronounced, the contending armies more or less great, the necessary movements more or less easy, but these are simply differences of scale, of degree, not of kind. As a wilderness gives place to civilization, as means of communication multiply, as roads are opened, rivers bridged, food-resources increased, the operations of war become easier, more rapid, more extensive; but the principles to which they must be conformed remain the same. When the march on foot was replaced by carrying troops in coaches, when the latter in turn gave place to railroads, the scale of distances was increased, or, if you will, the scale of time diminished; but the principles which dictated the point at which the army should be concentrated, the direction in which it should move, the part of the enemy's position which it should assail, the protection of communications, were not altered. So, on the sea, the advance from the galley timidly creeping from port to port to the sailing-ship launching out boldly to the ends of the earth, and from the latter to the steamship of our own time, has increased the scope and the rapidity of naval operations without necessarily changing the principles which should direct them; and the speech of Hermocrates twenty-three hundred years ago, before quoted, contained a correct strategic plan, which is as applicable in its principles now as it was then. Before hostile armies or fleets are brought into contact (a word which perhaps better than any other indicates the dividing line between tactics and strategy), there are a number of questions to be decided, covering the whole plan of operations throughout the theatre of war. Among these are the proper function of the navy in the war; its true objective; the point or points upon which it should be concentrated; the establishment of depots of coal and supplies; the maintenance of communications between these depots and the home base; the military value of commerce-destroying as a decisive or a secondary operation of war; the system upon which commerce-destroying can be most efficiently conducted, whether by scattered cruisers or by holding in force some vital centre through which commercial shipping must pass. All these are strategic questions, and upon all these history has a great deal to say. There has been of late a valuable discussion in English naval circles as to the comparative merits of the policies of two great English admirals, Lord Howe and Lord St. Vincent, in the disposition of the English navy when at war with France. The question is purely strategic, and is not of mere historical interest; it is of vital importance now, and the principles upon which its decision rests are the same now as then. St. Vincent's policy saved England from invasion, and in the hands of Nelson and his brother admirals led straight up to Trafalgar.
It is then particularly in the field of naval strategy that the teachings of the past have a value which is in no degree lessened. They are there useful not only as illustrative of principles, but also as precedents, owing to the comparative permanence of the conditions. This is less obviously true as to tactics, when the fleets come into collision at the point to which strategic considerations have brought them. The unresting progress of mankind causes continual change in the weapons; and with that must come a continual change in the manner of fighting,--in the handling and disposition of troops or ships on the battlefield. Hence arises a tendency on the part of many connected with maritime matters to think that no advantage is to be gained from the study of former experiences; that time so used is wasted. This view, though natural, not only leaves wholly out of sight those broad strategic considerations which lead nations to put fleets afloat, which direct the sphere of their action, and so have modified and will continue to modify the history of the world, but is one-sided and narrow even as to tactics. The battles of the past succeeded or failed according as they were fought in conformity with the principles of war; and the seaman who carefully studies the causes of success or failure will not only detect and gradually assimilate these principles, but will also acquire increased aptitude in applying them to the tactical use of the ships and weapons of his own day. He will observe also that changes of tactics have not only taken place after changes in weapons, which necessarily is the case, but that the interval between such changes has been unduly long. This doubtless arises from the fact that an improvement of weapons is due to the energy of one or two men,