Alfred T. Mahan
Alfred T. Mahan; drawing by David Levine

The next compiler of a dictionary of British and American English would do the speakers of each a service if he included the proper name Mahan and the explanation that in Britain it is pronounced to rhyme with barn but in the United States with Japan. A considerable number of Transatlantic conversations would be rescued from foundering in the opening stages on mutual incomprehension. For Mahan is still a name to conjure with, both that of Dennis Hart, teacher of strategy to the generals, North and South, of the American Civil War, and his son Alfred Thayer, prophet of the creed of seapower to the Anglo-Saxon world.

Dennis, protégé of Sylvanus Thayer, the “Father of West Point,” taught there throughout his adult life. Indeed, so precocious was he that he was appointed an assistant professor while still following the course as a cadet. Though like many prodigies an imitator rather than an innovator, he propagated the ideas of his master, the early nineteenth-century Swiss general and military writer, Antoine Henri Jomini, and did so with such force and clarity that his teaching indelibly marked the professional practice of many of his pupils. By no means for the better: Jomini’s central idea, derived from a partial understanding of Napoleon’s methods, was that success in war turned on choosing the correct “line of operations” and dominating the theater of battle through which it ran. McClellan’s disastrous Peninsular campaign of 1862 is held to be the most perfect example of a Jominian campaign ever fought, admittedly by a temperamental defeatist. The great victories of the Civil War were won by two ex-pupils, Sherman and Grant, who flagrantly broke every one of the classroom rules. The professor nevertheless went to his grave (curiously a watery one) in the odor of military sanctity, and would still be remembered, at least in the professional circles, even had he died childless.

He had certainly by 1871 given no expectation that his son would add refulgence to the family name. Alfred was then a junior naval officer, unremarkable save for his religious scrupulosity and air of intellectual remoteness, enhanced by his great height. He continued unremarkable for the next twenty years, eking out an obscure career aboard a succession of decrepit naval ships whose romantic Fenimore Cooper names—Iroquois, Monocacy, Seminole, Wachusett—were the most warlike thing about them. Starved of money, like the navy itself, he took refuge in France when he was put on half pay. He then made his first shot at writing—about cathedral architecture—and it was the same financial want that prompted him in 1883 to accept a beggarly commission from Scribner’s for a volume in its history of the navy in the Civil War.

The rather pedestrian result nevertheless persuaded the first commandant of the new Naval War College that the author was the man to lecture its students on naval strategy, and he sent for him. The call when it came found Mahan commanding the Wachusset off Callao, Peru. Almost any excuse would have been good enough to tempt Mahan off her permanently listing quarter-deck, and he took leave to begin the necessary course of preparatory reading in the library of the English Club at Lima.

The library’s resources were limited, so limited that only the most remarkable mind could have drawn from them the stuff of a new theory of universal history. Mahan, indeed, would in later life claim that his inspiration came from outside himself, illuminating his understanding of Mommsen’s History of Rome—the solidest material the library could provide—with a flash of divine fire. What it showed him was that Carthage, far from having been defeated on land, had ultimately gone down to defeat because of Rome’s control of the waters of the Mediterranean. If that truth, and others akin, had been hither-to hidden from the world it was because—to quote from this new and magnificently illustrated abridgment of his two most famous works—

the navy acts on an element strange to most writers, its members have been from time immemorial a strange race apart, without prophets of their own, neither themselves nor their calling understood and its immense determining influence upon the history of the world has been consequently overlooked.

During the next six years Mahan established the idea of “the influence of sea power” on apparently unshakable empirical foundations; within ten years he was accepted as a prophet of state policy without equal in his own time.

The pace of Mahan’s intellectual activity, once begun, was phenomenal. Sea duty kept him in the Pacific until October 1885, when he began a ten-month sabbatical in New York. During those months he produced the course of lectures which was to become The Influence of Sea Power upon History, 1660-1783, 540 pages long. Those which would become The Influence of Sea Power upon the French Revolution and Empire, amounting when published to 791 printed pages, were written between the fall of 1891 and November 1892. In the intervals he taught his classes at the War College, led a commission to site a new naval base in Washington Territory, drafted a contingency war plan for the secretary of the navy, and wrote a full-scale biography of Admiral Farragut. But it was the first book that engaged his heart and made his name. He had some difficulty finding a publisher for it and was reduced at one stage to soliciting a loan from J.P. Morgan to cover the printing costs (the financier offered $200). Eventually Little, Brown were persuaded to take the risk and it appeared in May 1890 to reviews that were from the first admiring and to expressions of private opinion that were often adulatory.


Many of these were British and not surprisingly, for it was in the history of the Royal Navy that he found the material for his theory. How was it, he asked, that a comparatively small and unpopulous island had come to stand first among nations of the modern world? The answer, he argued, depended on six factors, the presence or absence of which would always determine whether or not a country would emerge as a sea power. First was geographical position; then came physical conformation, extent of territory, size of population, national character, and type of government. Britain’s position astride the sea approaches to northern Europe and her plenitude of fine harbors made her a natural naval base. The ratio of her size to her population and the engagement of so many of her people in sea-faring provided her with the fundamentals of naval power. Her commercial and productive capacities furnished her with a motive toward its exercise. The entrenchment of the government in a ruling class dedicated to the country’s best interests ensured that the nation would be held to the sacrifices which the exercise of a strong naval policy entailed.

But the rewards of sea power would not flow automatically from the possession of its fundamentals. It must be applied with precision, consistency, and force. The sea “is a wide common, over which men may pass in all directions, but on which some well-worn paths show that controlling reasons have led them to choose certain lines of travel rather than others.” In war one combatant may inflict heavy damage on another by raiding these trade routes and may be content with the local and temporary successes thus achieved, as was the case with France in the seventeenth and eighteenth centuries. Or a power may choose to use those routes but occasionally, devoting its naval strength to the protection of rare, rich convoys, as with Spain and its bullion fleets. Neither strategy will avail against a power which builds and maintains a navy fit to keep the seas at all times and powerful enough to defeat any force opposed to it. Not only will it win local victories, which will be very costly to a convoying power. It will in time acquire a network of overseas bases which will confine a navy suited merely to raiding commerce to its home ports. Parsimony, in short, is a false economy in naval strategy. A big fleet, though costly, reaps rewards out of all proportion to its expense because its ability to fight “decisive battles” ensures “Command of the Sea,” from which in turn flows national greatness.

Mahan’s message was music to British ears and when in 1894 his captaincy of the Chicago brought him to England he was lionized: Oxford and Cambridge conferred doctorates on him and he was twice received by Queen Victoria. But the music was a siren’s song. It undoubtedly strengthened the hands of those British navalists who were pressing for yet further additions to the battle fleet. But it also struck chords among the naval have-not and would-not nations, who wanted to ensure that Britain’s preponderant naval power would be first challenged and then surpassed.

First among the have-nots was Germany, whose Kaiser had met Mahan at his English grandmother’s court in 1893 and become not only one of his most fervent admirers—“I am devouring Captain Mahan’s book and trying to learn it by heart”—but, through the enactment of the naval laws of the 1890s, a dynamic practical convert. His navy, like America’s, had previously been little better than a coast-defense force. By 1890 it was about to emerge as the second in the world, large enough to pull many British ships homeward from their colonial outposts and at the same time to provide detached squadrons for Germany’s own expanding network of colonies in Africa and the Pacific. Germany challenged British naval power not only strategically but also technologically. Its ships, as befitted the land of Krupp, Siemens, and Zeiss, were wonders of speed, strength, and gunpower. Their quality compelled the British, already an industrial power in decline, to the effort of outmatching them not only in numbers but ultimately in design.


The decision to launch the revolutionary Dreadnought in 1906 may have successfully rendered obsolescent all the battlefleets of the world. It also committed Britain to a yet more frantic arms race than she had run before; the effort to sustain that race cost her more than she could afford in money and, more important, in national nervous energy. The spectacle of the Germans inexorably fitting themselves to fight that “big battle” which Mahan taught was the test of naval supremacy encouraged a psychological mood of wishing it could take place sooner rather than later. This explains Sir Charles Webster’s famous aside, “Mahan was one of the causes of the First World War.”

Mahan’s influence in the New World was as dramatic as in the Old, and even longer-lasting. The policy of the United States, a would-not naval power, was transformed within the decade in which his great books appeared, largely because of the grist they lent to the imperialist mills of politicians like Theodore Roosevelt. Mahan himself, originally a pure academic, had become an imperialist by 1898 and therefore warmly welcomed the war with Spain and the accessions of territory it brought both in the Caribbean and the far Pacific. There is little doubt that he would also have welcomed the policies which flowed from those acquisitions, of involvement in mainland China in the 1930s and confrontation with Japan in the 1940s. Even those who opposed the “big navy” that he fathered before the First World War could not have denied that his “decisive battle” theory was vindicated in every respect by the sequence of victories which flowed uninterrupted from Midway to Leyte Gulf during World War II.

And yet doubt must linger around both the right and the desirability of Mahanism. It consists in essence of two separate theories, one of force, the other of geopolitics, which are but tenuously connected. With the force theory, which is classical in nature and akin to those of Jomini and Clausewitz, there is little to argue. A big fleet, properly handled and maintained, must in the long run establish mastery over a smaller fleet, and the quickest way for it to do so is to seek out a major fleet action.

The geopolitical theory is altogether shakier. For it rests on the belief that communication by sea is superior to communication by land. In Nelson’s, even in Mahan’s day, the belief was correct. In our own it looks much more dubious. The Vietnam war, which may be seen as Mahan’s ultimate strategic bequest to the United States, pitted sea against land communications at a point where, even fifty years ago, the former should have prevailed. But all the force delivered by the United States Navy did not cut the Ho Chi Minh Trail; nor could it as long as America shrank from the Mahanian prescription of making one and perhaps both the Vietnams a colony. For that there was even less popular consent than for the prosecution of the war itself; and how much more would there be today for the colonization or firm political control of every terminal of sea power at which America’s vital interests are threatened? As road, rail, and internal air communication improve, Mahanism nevertheless drives strategic policy toward such an end, so paradoxically transforming it into a theory not of sea but of land power.

Perhaps, while the dependence of the US on overseas oil remains undiminished, it cannot escape the need to establish and maintain a permanent naval presence in the oil-bearing regions. If the US is to remain an Atlantic power, it must retain the means to communicate safely with Europe across the ocean. But if, provoked by the growth of Russian seapower (the objects of which may be strictly limited), it seeks to sustain dominion over the world oceans, of the sort exercised by the Royal Navy in the era which inflamed Mahan’s imagination, it may find, as post-Victorian Britain did, that the cost exceeds even its mighty resources.

This Issue

February 5, 1981