The Interest of America in Sea Power, Present and Future

by A. T. Mahan

June, 1897.

The importance, absolute and relative, of portions of the earth's surface, and their consequent interest to mankind, vary from time to time. The Mediterranean was for many ages the centre round which gathered all the influences and developments of those earlier civilizations from which our own, mediately or immediately, derives. During the chaotic period of struggle that intervened between their fall and the dawn of our modern conditions, the Inland Sea, through its hold upon the traditions and culture of antiquity, still retained a general ascendency, although at length its political predominance was challenged, and finally overcome, by the younger, more virile, and more warlike nationalities that had been forming gradually beyond the Alps, and on the shores of the Atlantic and Northern oceans. It was, until the close of the Middle Ages, the one route by which the East and the West maintained commercial relations; for, although the trade eastward from the Levant was by long and painful land journeys, over mountain range and desert plain, water communication, in part and up to that point, was afforded by the Mediterranean, and by it alone. With the discovery of the passage by the Cape of Good Hope this advantage departed, while at the same instant the discovery of a New World opened out to the Old new elements of luxury and a new sphere of ambition. Then the Mediterranean, thrown upon its own productive resources alone, swayed in the East by the hopeless barbarism of the Turk, in the West by the decadent despotism of Spain, and, between the two, divided among a number of petty states, incapable of united and consequently of potent action, sank into a factor of relatively small consequence to the onward progress of the world. During the wars of the French Revolution, when the life of Great Britain, and consequently the issue of the strife, depended upon the vigor of British commerce, British merchant shipping was nearly driven from that sea; and but two per cent of a trade that was increasing mightily all the time was thence derived. How the Suez Canal and the growth of the Eastern Question, in its modern form, have changed all that, it is needless to say. Yet, through all the period of relative insignificance, the relations of the Mediterranean to the East and to the West, in the broad sense of those expressions, preserved to it a political importance to the world at large which rendered it continuously a scene of great political ambitions and military enterprise. Since Great Britain first actively intervened in those waters, two centuries ago, she at no time has surrendered willingly her pretensions to be a leading Mediterranean Power, although her possessions there are of purely military, or rather naval, value.

The Caribbean Sea and the Gulf of Mexico, taken together, form an inland sea and an archipelago. They too have known those mutabilities of fortune which receive illustration alike in the history of countries and in the lives of individuals. The first scene of discovery and of conquest in the New World, these twin sheets of water, with their islands and their mainlands, became for many generations, and nearly to our own time, a veritable El Dorado,—a land where the least of labor, on the part of its new possessors, rendered the largest and richest returns. The bounty of nature, and the ease with which climatic conditions, aided by the unwarlike character of most of the natives, adapted themselves to the institution of slavery, insured the cheap and abundant production of articles which, when once enjoyed, men found indispensable, as they already had the silks and spices of the East. In Mexico and in Peru were realized also, in degree, the actual gold-mine sought by the avarice of the earlier Spanish explorers; while a short though difficult tropical journey brought the treasures of the west coast across the Isthmus to the shores of the broad ocean, nature's great highway, which washed at once the shores of Old and of New Spain. From the Caribbean, Great Britain, although her rivals had anticipated her in the possession of the largest and richest districts, derived nearly twenty-five per cent of her commerce, during the strenuous period when the Mediterranean contributed but two per cent.

But over these fair regions too passed the blight, not of despotism merely, for despotism was characteristic of the times, but of a despotism which found no counteractive, no element of future deliverance, in the temperament or in the political capacities of the people over whom it ruled. Elizabeth, as far as she dared, was a despot; Philip II. was a despot; but there was already manifest in her subjects, while there was not in his, a will and a power not merely to resist oppression, but to organize freedom. This will and this power, after gaining many partial victories by the way, culminated once for all in the American Revolution. Great Britain has never forgotten the lesson then taught; for it was one she herself had been teaching for centuries, and her people and statesmen were therefore easy learners. A century and a quarter has passed since that warning was given, not to Great Britain only, but to the world; and we to-day see, in the contrasted colonial systems of the two states, the results, on the one hand of political aptitude, on the other of political obtuseness and backwardness, which cannot struggle from the past into the present until the present in turn has become the past—irreclaimable.

Causes superficially very diverse but essentially the same, in that they arose from and still depend upon a lack of local political capacity, have brought the Mediterranean and the Caribbean, in our own time, to similar conditions, regarded as quantities of interest in the sphere of international relations. Whatever the intrinsic value of the two bodies of water, in themselves or in their surroundings, whatever their present contributions to the prosperity or to the culture of mankind, their conspicuous characteristics now are their political and military importance, in the broadest sense, as concerning not only the countries that border them, but the world at large. Both are land-girt seas; both are links in a chain of communication between an East and a West; in both the chain is broken by an isthmus; both are of contracted extent when compared with great oceans, and, in consequence of these common features, both present in an intensified form the advantages and the limitations, political and military, which condition the influence of sea power. This conclusion is notably true of the Mediterranean, as is shown by its history. It is even more forcibly true of the Caribbean, partly because the contour of its shores does not, as in the Mediterranean peninsulas, thrust the power of the land so far and so sustainedly into the sea; partly because, from historical antecedents already alluded to, in the character of the first colonists, and from the shortness of the time the ground has been in civilized occupation, there does not exist in the Caribbean or in the Gulf of Mexico—apart from the United States—any land power at all comparable with those great Continental states of Europe whose strength lies in their armies far more than in their navies. So far as national inclinations, as distinct from the cautious actions of statesmen, can be discerned, in the Mediterranean at present the Sea Powers, Great Britain, France, and Italy, are opposed to the Land Powers, Germany, Austria, and Russia; and the latter dominate action. It cannot be so, in any near future, in the Caribbean. As affirmed in a previous paper, the Caribbean is pre-eminently the domain of sea power. It is in this point of view—the military or naval—that it is now to be considered. Its political importance will be assumed, as recognized by our forefathers, and enforced upon our own attention by the sudden apprehensions awakened within the last two years.

It may be well, though possibly needless, to ask readers to keep clearly in mind that the Caribbean Sea and the Gulf of Mexico, while knit together like the Siamese twins, are distinct geographical entities. A leading British periodical once accused the writer of calling the Gulf of Mexico the Caribbean Sea, because of his unwillingness to admit the name of any other state in connection with a body of water over which his own country claimed predominance. The Gulf of Mexico is very clearly defined by the projection, from the north, of the peninsula of Florida, and from the south, of that of Yucatan. Between the two the island of Cuba interposes for a distance of two hundred miles, leaving on one side a passage of nearly a hundred miles wide—the Strait of Florida—into the Atlantic, while on the other, the Yucatan Channel, somewhat broader, leads into the Caribbean Sea. It may be mentioned here, as an important military consideration, that from the mouth of the Mississippi westward to Cape Catoche—the tip of the Yucatan Peninsula—there is no harbor that can be considered at all satisfactory for ships of war of the larger classes. The existence of many such harbors in other parts of the regions now under consideration practically eliminates this long stretch of coast, regarded as a factor of military importance in the problem before us.

In each of these sheets of water, the Gulf of Mexico and the Caribbean, there is one position of pre-eminent commercial importance. In the Gulf the mouth of the Mississippi is the point where meet all the exports and imports, by water, of the Mississippi Valley. However diverse the directions from which they come, or the destinations to which they proceed, all come together here as at a great crossroads, or as the highways of an empire converge on the metropolis. Whatever value the Mississippi and the myriad miles of its subsidiary water-courses represent to the United States, as a facile means of communication from the remote interior to the ocean highways of the world, all centres here at the mouth of the river. The existence of the smaller though important cities of the Gulf coast—Mobile, Galveston, or the Mexican ports—does not diminish, but rather emphasizes by contrast, the importance of the Mississippi entrance. They all share its fortunes, in that all alike communicate with the outside world through the Strait of Florida or the Yucatan Channel.

In the Caribbean, likewise, the existence of numerous important ports, and a busy traffic in tropical produce grown within the region itself, do but make more striking the predominance in interest of that one position known comprehensively, but up to the present somewhat indeterminately, as the Isthmus. Here again the element of decisive value is the crossing of the roads, the meeting of the ways, which, whether imposed by nature itself, as in the cases before us, or induced, as sometimes happens, in a less degree, by simple human dispositions, are prime factors in mercantile or strategic consequence. For these reasons the Isthmus, even under the disadvantages of land carriage and transshipment of goods, has ever been an important link in the communications from East to West, from the days of the first discoverers and throughout all subsequent centuries, though fluctuating in degree from age to age; but when it shall be pierced by a canal, it will present a maritime centre analogous to the mouth of the Mississippi. They will differ in this, that in the latter case the converging water routes on one side are interior to a great state whose resources they bear, whereas the roads which on either side converge upon the Isthmus lie wholly upon the ocean, the common possession of all nations. Control of the latter, therefore, rests either upon local control of the Isthmus itself, or, indirectly, upon control of its approaches, or upon a distinctly preponderant navy. In naval questions the latter is always the dominant factor, exactly as on land the mobile army—the army in the field—must dominate the question of fortresses, unless war is to be impotent.

We have thus the two centres round which revolve all the military study of the Caribbean Sea and the Gulf of Mexico. The two sheets of water, taken together, control or affect the approaches on one side to these two supreme centres of commercial, and therefore of political and military, interest. The approaches on the other side—the interior communications of the Mississippi, that is, or the maritime routes in the Pacific converging upon the Isthmus—do not here concern us. These approaches, in terms of military art, are known as the "communications." Communications are probably the most vital and determining element in strategy, military or naval. They are literally the most radical; for all military operations depend upon communications, as the fruit of a plant depends upon communication with its root. We draw therefore upon the map the chief lines by which communication exists between these two centres and the outside world. Such lines represent the mutual dependence of the centres and the exterior, by which each ministers to the others, and by severance of which either becomes useless to the others. It is from their potential effect upon these lines of communication that all positions in the Gulf or the Caribbean derive their military value, or want of value.

It is impossible to precede or to accompany a discussion of this sort with a technical exposition of naval strategy. Such definitions of the art as may be needed must be given in loco , cursorily and dogmatically. Therefore it will be said here briefly that the strategic value of any position, be it body of land large or small, or a seaport, or a strait, depends, 1, upon situation (with reference chiefly to communications), 2, upon its strength (inherent or acquired), and, 3, upon its resources (natural or stored). As strength and resources are matters which man can accumulate where suitable situation offers, whereas he cannot change the location of a place in itself otherwise advantageous, it is upon situation that attention must primarily be fixed. Strength and resources may be artificially supplied or increased, but it passes the power of man to move a port which lies outside the limits of strategic effect. Gibraltar in mid-ocean might have fourfold its present power, yet would be valueless in a military sense.