The Influence of Sea Power upon History. Alfred Thayer Mahan
of sea power placed upon the career of France may mourn that their own country is being led, by a like redundancy of home wealth, into the same neglect of that great instrument.
Among modifying physical conditions may he noted a forum Like that of Italy,--a long peninsula, with a central range of mountains dividing it unto two narrow strips, along which the roads connecting the different ports necessarily run. Only an absolute control of the sea can wholly secure such communications, since it is impossible to know at what point an enemy coming from beyond the visible horizon may strike but still, with an adequate naval force centrally posted, there will be good hope of attacking his fleet, which is at once his base and line of communications, before serious damage has been done. The long, narrow peninsula of Florida, with Key West at its extremity, though flat and thinly populated, presents at first sight conditions like those of Italy. The resemblance may be only superficial, but it seems probable that if the chief scene of a naval war were the Gulf of Mexico, the communications by land to the end of the peninsula might be a matter of consequence, and open to attack.
When the sea not only borders, or surrounds, but also separates a country into two or more parts, the control of it becomes not only desirable, but vitally necessary. Such a physical condition either gives birth and strength to sea power, or makes the country powerless. Such is the condition of the present kingdom of Italy, with its islands of Sardinia and Sicily; and hence in its youth and still existing financial weakness it is seen to put forth such vigorous and intelligent efforts to create a military navy. It has even been argued that, with a navy decidedly superior to her enemy's, Italy could better base her power upon her islands than upon her mainland; for the insecurity of the lines of communication in the peninsula, already pointed out, would most seriously embarrass an invading army surrounded by a hostile people and threatened from the sea.
The Irish Sea, separating the British Islands, rather resembles an estuary than an actual division; but history has shown the danger from it to the United Kingdom. In the days of Louis XIV., when the French navy nearly equalled the combined English and Dutch, the gravest complications existed in Ireland. which passed almost wholly under the control of the natives and the French. Nevertheless, the Irish Sea was rather a danger to the English--a weak point in their communications --than an advantage to the French. The latter did not venture their ships-of-the-line in its narrow waters, and expeditions intending to land were directed upon the ocean ports in the south and west. At the supreme moment the great French fleet was sent upon the south coast of England, where it decisively defeated the allies, and at the same the twenty-five frigates were sent to St. George's Channel, against the English communications. In the midst of a hostile people, the English army in Ireland was seriously imperiled, but was saved by the battle of the Boyne and the flight of James II. This movement against the enemy's communications was strictly strategic, and would be just as dangerous to England now as in 1690.
Spain, in the same century afforded an impressive lesson of the weakness caused by such separation when the parts are not knit together by a strong sea power. She then still retained, as remnants of her past greatness, the Netherlands (now Belgium), Sicily, and other Italian possessions, not to speak of her vast colonies in the New World. Yet so low had the Spanish sea power fallen, that a well-informed and sober-minded Hollander of the day could claim that "in Spain all the coast is navigated by a few Dutch ships and since the peace of 1648 their ships and seamen are so few that they have publicly begun to hire our ships to sail to the Indies, whereas they were formerly careful to exclude all foreigners from there … It is manifest," he goes on, "that the West Indies. being as the stomach to Spain (for from it nearly all the revenue is drawn), must be joined to the Spanish head by a sea force; and that Naples and the Netherlands, being like two arms, they cannot lay out their strength for Spain, nor receive anything thence but by shipping,--all which may easily be done by our shipping in peace, and by it obstructed in war." Half a century before, Sully, the great minister of Henry IV., had characterized Spain "as one of those States whose legs and arms are strong and powerful, but the heart infinitely weak and feeble." Since his day the Spanish navy had suffered not only disaster, but annihilation; not only humiliation, but degradation. The consequences briefly were that shipping was destroyed; manufactures perished with it. The government depended for its support, not upon a wide-spread healthy commerce and industry that could survive many a staggering blow, but upon a narrow stream of silver trickling through a few treasure-ships from America, easily and frequently intercepted by an enemy's cruisers. The loss of half a dozen galleons more than once paralyzed its movements for a year. While the war in the Netherlands lasted, the Dutch control of the sea forced Spain to send her troops by a long and costly journey overland instead of by sea; and the same cause reduced her to such straits for necessaries that, by a mutual arrangement which seems very odd to modern ideas, her wants were supplied by Dutch ships, which thus maintained the enemies of their country, but received in return specie which was welcome in the Amsterdam exchange. In America, the Spanish protected themselves as best they might behind masonry, unaided from home; while in the Mediterranean they escaped insult and injury mainly through the indifference of the Dutch, for the French and English had not yet begun to contend for mastery there. In the course of history the Netherlands, Naples, Sicily, Minorca, Havana, Manila, and Jamaica were wrenched away, at one time or another, from this empire without a shipping. In short, while Spain's maritime impotence may have been primarily a symptom of her general decay, it became a marked factor in precipitating her into the abyss from which she has not yet wholly emerged.
Except Alaska, the United States has no outlying possession,--no foot of ground inaccessible by land. Its contour is such as to present few points specially weak from their saliency, and all important parts of the frontiers can be readily attained,--cheaply by water, rapidly by rail. The weakest frontier, the Pacific, is far removed from the most dangerous of possible enemies. The internal resources are boundless as compared with present needs; we can live off ourselves indefinitely in "our little corner," to use the expression of a French officer to the author. Yet should that little corner be invaded by a new commercial route through the Isthmus, the United States in her turn may have the rude awakening of those who have abandoned their share in the common birthright of all people, the sea.
III. Extent of Territory. The last of the conditions affecting the development of a nation as a sea power, and touching the country itself as distinguished from the people who dwell there, is Extent of Territory. This may be dismissed with comparatively few words.
As regards the development of sea power, it is not the total number of square miles which a country contains, but the length of its coast-line and the character of its harbors that are to be considered. As to these it is to be said that, the geographical and physical conditions being the same, extent of sea-coast is a source of strength or weakness according as the population is large or small. A country is in this like a fortress; the garrison must be proportioned to the _enceinte_. A recent familiar instance is found in the American War of Secession. Had the South had a people as numerous as it was warlike, and a navy commensurate to its other resources as a sea power, the great extent of its sea-coast and its numerous inlets would have been elements of great strength. The people of the United States and the Government of that day justly prided themselves on the effectiveness of the blockade of the whole Southern coast. It was a great feat, a very great feat; but it would have been an impossible feat had the Southerners been more numerous, and a nation of seamen. What was there shown was not, as has been said, how such a blockade can be maintained, but that such a blockade is possible in the face of a population not only unused to the sea, but also scanty in numbers. Those who recall how the blockade was maintained, and the class of ships that blockaded during great part of the war, know that the plan, correct under the circumstances, could not have been carried out in the face of a real navy. Scattered unsupported along the coast, the United States ships kept their places, singly or in small detachments, in face of an extensive network of inland water communications which favored secret concentration of the enemy. Behind the first line of water communications were long estuaries, and here and there strong fortresses, upon either of which the enemy's ships could always fall back to elude pursuit or to receive protection. Had there been a Southern navy to profit by such advantages, or by the scattered condition of the United States ships, the latter could not have been distributed as they were; and being forced to concentrate for mutual support, many small but useful approaches would have been left open to commerce. But as the Southern coast, from