Alfred Thayer Mahan - The Influence of Sea Power Upon History, 1660-1783

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 con tact (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, while changes in tactics have to overcome the inertia of a conservative class; but it is a great evil. It can be remedied only by a candid recognition of each change, by careful study of the powers and limitations of the new ship or weapon, and by a consequent adaptation of the method of using it to the qualities it possesses, which will constitute its tactics. History shows that it is vain to hope that military men generally will be at the pains to do this, but that the one who does will go into battle with a great advantage,—a lesson in itself of no mean value.

We may therefore accept now the words of a French tactician, Morogues, who wrote a century and a quarter ago: "Naval tactics are based upon conditions the chief causes of which, namely the arms, may change; which in turn causes necessarily a change in the construction of ships, in the manner of handling them, and so finally in the disposition and handling of fleets." His further statement, that "it is not a science founded upon principles absolutely invariable," is more open to criticism. It would be more correct to say that the application of its principles varies as the weapons change. The application of the principles doubtless varies also in strategy from time to time, but the variation is far less; and hence the recognition of the underlying principle is easier. This statement is of sufficient importance to our subject to receive some illustrations from historical events.

The battle of the Nile, in 1798, was not only an overwhelming victory for the English over the French fleet, but had also the decisive effect of destroying the communications between France and Napoleon's army in Egypt. In the battle itself the English admiral, Nelson, gave a most brilliant example of grand tactics, if that be, as has been defined, "the art of making good combinations preliminary to battles as well as during their progress." The particular tactical combination depended upon a condition now passed away, which was the inability of the lee ships of a fleet at anchor to come to the help of the weather ones before the latter were destroyed; but the principles which underlay the combination, namely, to choose that part of the enemy's order which can least easily be helped, and to attack it with superior forces, has not passed away. The action of Admiral Jervis at Cape St. Vincent, when with fifteen ships he won a victory over twenty-seven, was dictated by the same principle, though in this case the enemy was not at anchor, but under way. Yet men's minds are so constituted that they seem more impressed by the transiency of the conditions than by the undying principle which coped with them. In the strategic effect of Nelson's victory upon the course of the war, on the contrary, the principle involved is not only more easily recognized, but it is at once seen to be applicable to our own day. The issue of the enterprise in Egypt depended upon keeping open the communications with France. The victory of the Nile destroyed the naval force, by which alone the communications could be assured, and determined the final failure; and it is at once seen, not only that the blow was struck in accordance with the principle of striking at the enemy's line of communication, but also that the same principle is valid now, and would be equally so in the days of the galley as of the sailing-ship or steamer.