It is the fate of most great teachers that their doctrines are met at first by indifference or hostility, but later, when generally accepted, they are carried to lengths of interpretation and sanctification that the masters themselves never intended. Something of this latter state has now fallen upon Admiral Mahan. Having demonstrated the importance of sea-power in history by principles and evidence beyond dispute, he has been succeeded by a school of journalistic war critics who write of sea-power as if it were in itself a talisman against defeat, as if there were some inherent magic in sea-power that could always be depended onto bring victory. And in every such utterance the name of Mahan is brought in, to bolster up a generalization which he himself might be the last to accept.

Thus, during the blackest days of the war, English and American ‘war experts’ assured us placidly that everything would come out all right because England held the sea. The Allies, therefore, could not lose. Now that the war is over, these same experts and others swell the chorus that ‘sea-power won the war.’ One enthusiastic Englishman, for instance, exclaims, ‘Armies are, after all, only the projectiles of the navy.’ There is just enough truth in these statements to sweep the reader into conclusions that are utterly false, and to make of Mahan’s famous phrase, not a scientific principle, but a shibboleth.

At the outset, it is impossible to call attention to the difference between saying that sea-power proved decisive and that ‘sea-power won the war.’ The latter statement carries an unjust implication concerning the other forces that may, in fact, have borne the greater burden of the conflict. Thus, it is fair to say that the entry of the United States was decisive, but to say that America won the war would be a silly boast. Mahan says, of the Union navy, ‘Never in history did sea-power play so decisive a part’; yet no one would say that it ‘won’ the Civil War, because the effectiveness of the fleet was wholly dependent on the parallel effectiveness of the army. The South fell a victim to the blockade, because of its need of manufactured articles from the outside world. If, however, Lee had broken through at Gettysburg and captured Philadelphia and Washington, Northern sea-power would have availed little or nothing, because the South would have gained its necessities by conquest and ended the war.

If it would be going too far to assert that the Union navy won the Civil War, what shall be said of the British navy in this war? Conditions, in the two wars, were, of course, vastly different: for one thing, the South had no navy whatever at the opening of the war. Nevertheless, in judging the comparative weight of sea-power in the two conflicts, we have every right to consider simply the results.

What did the Union navy accomplish? It opened the entire length of the Mississippi, thus splitting the Confederacy in two, carrying the war by water, up the tributaries, into the very heart of the South, and creating a western line of blockade. It captured the important seaports, one after another. It maintained a blockade that made increasingly difficult the exchange of cotton for manufactured goods on which the South depended for its life, and finally shut it off completely. At the same time, except for the depredations of the Alabama, the seas were kept open for the commerce and other communications of the North. These services make an impressive total, even in the briefest summary.

What, by comparison, have been the results attained by British sea-power? On the side of strictly strategic or tactical achievement, the story is disappointing. There has been no New Orleans or Mobile Bay, to say nothing of a Nile or Trafalgar. In fact, things seem to have missed fire since the day the Goeben and the Breslau slipped through the Mediterranean fleet at the very outbreak of the war. There was the failure to send adequate support to Cradock in the Pacific. There was the futile ten-minute bombardment of the Dardanelles forts a little later, resulting only in warning the Turks to improve their defenses; and in the following March, the abandonment of the naval attack on the straits at a time when one more day’s push would have won the great prize. This failure has been characterized by Mr. Pollen, the English naval critic, as ‘the greatest blunder in naval history.’

It is still more difficult to understand why Jellicoe did not close with the beaten German fleet at Jutland; why he lost contact with it during the night after the action; and why, on the following morning, he abandoned his position between that fleet and its bases. And why, after the ruthless submarine campaign was inaugurated, did it require three terrible months of destruction to make the Admiralty realize the necessity of the convoy system? The one bright spot is made by the dashing and successful attacks on Zeebrugge and Ostend; but even these raise the query why they were not carried out about four years earlier. In fact, the governing policy suggests that of the French navy in the eighteenth century, which figured on what might happen in case of defeat, rather than on running certain risks for the sake of a decisive victory. To the layman, at any rate, the suspicion is hard to overcome, that sea0power with a more aggressive strategy might have accomplished considerably more.

As to the services of the British blockade, we have the statement of an American admiral that it was the ‘greatest contributing cause of Germany’s ultimate collapse’; but the fact may be debated. This blockade, on account of German mines and submarines, was carried on under the most difficult conditions, and to make it effective at all, international law was put to considerable strain. The small neutrals were practically put on rations; the old distinction between contraband and non-contraband was thrown overboard; and the real pressure of the blockade was felt only when the largest neutral came in on the side of sea-power. In spite of every effort to make the blockade effective, it appears since the armistice that neither the German people nor the German army were in the dire straits that we had fondly imagined. The statement has been issued from Washington that, at the time of the surrender, Germany had eight months’ supply of food on hand, and that the October harvest was fifteen per cent more abundant than ever before. Indeed, it is doubtful if there was as much actual scarcity of food and fuel in Germany at that time as there was in Italy, which has been on the side of sea-power. Undoubtedly the blockade of the Central Powers was felt and felt keenly, but it never reached the crushing effect of the Union blockade of the South. The reason for this difference will be apparent later, when we analyze the significance of sea-power.

On the defensive side, however, that of maintaining communications, the service of British sea-power has been enormous. In this respect it has been the keystone of the Allied cause. It has swept German commerce from the sea, isolated German colonies, maintained contact with all parts of the British Empire, its allies, and neutral sources of supply. With the naval resources of its allies, it has also conquered the pirate submarine. Finally, British sea-power was the chief means by which the United States army was enabled at the critical point of the war to deliver the decisive blow. These services have been of the utmost importance, and they have been performed under unprecedented difficulties and with the greatest heroism and devotion to duty; but they have consisted mainly in holding for the Allies the highways of the sea as lines of supply. The army man, therefore, who remarks that in this war the navy has been ‘only a commissary wagon for the army,’ has fully as much truth on his side as the naval enthusiast who says that ‘armies are only the projectiles of the navy.’

Naval power, as Mahan says, is like FitzJames’s blade, ‘both sword and shield.’ The Union navy was emphatically both, and its greatest service was as the sword. British naval power in this war has been almost entirely shield. Sea-power has been on the defensive. Hence to claim for sea-power in this war what one would not claim for sea-power in the Civil War is singularly inappropriate. Moreover, it does not follow that nay single element was responsible for victory, simply because the war would have been lost without it. The war would as certainly have been lost without the French army. And, essential as sea-power has been to the Allied cause, it has been no magic Excalibur, as so many British writers seem to believe. On the contrary, Germany came within an acre of winning this war without sea-power, even as she won the Franco-Prussian War without it.

Let us suppose the saner heads in Berlin had carried the day against ruthless submarine warfare, and thus kept the United States out of the war until a more convenient season. The new fleet of U-boats completed by January, 1917, by virtue of their size, cruising radius, shell-guns, and mines, could have done great damage to Allied shipping without deviating from the requirements of the Sussex agreement. Aside from the submarine menace, events ran in a black flood against the Allied cause for a year and a half. Roumania was conquered at the close of 1916. The subsequent March brought the revolution in Russia, which proved to be only the beginning of her collapse. In April, Nivelle launched his bloody offensive and failed, with the result that a grave mutiny threatened the very existence of the French army, and women paraded the streets of Paris, waving the red flag and crying, ‘Rendez-nous nos soldats!’ (All of which, by the way, the censorship kept everybody but the Germans from knowing.) Throughout the summer and fall affairs in Russia went from bad to worse, until it became clear that there would be no longer an Eastern front, that the German armies of the east would be available to strike in France and Italy, and that the British blockade would not affect Germany’s access to the supplies of the Ukraine and the Black Sea. In October came the disaster of Caporetto, revealing the critical loss of morale in the Italian army. Both France and England were compelled to send troops they could ill spare, to bolster up the Piave line. At this time England was at the limit of her man-power, and yet was under the necessity of combing out of her armies the men who were needed for the vital industry of shipbuilding. And apparently the government had so little faith in its control of the sea, if ever the Germans captured Dunkirk and Calais and Boulogne, that it kept a large army in England to repel a possible invasion, and army that was not released for service in France until the arrival of American troops for training in British camps.

With the coming of 1918 Ludendorff’s machine was ready, and the story of its assaults is too fresh to need the telling. It was not so many months ago that we trembled for the fate of Paris and the Channel ports. It is reasonably certain that, without the reinforcements of the United States in troops, credit, supplies, and the morale created by the knowledge of our resources thrown into the struggle, France and Italy would have followed Russia, and that England, with her armies crushed on the Continent and the Channel ports in German hands, would not have lasted long as a solitary antagonist, in spite of her control of the sea. Napoleon needed sea-power to control the Channel crossing, but with the power of modern artillery the Germans could have controlled the passage from fortification ashore. Under these conditions, even if an actual invasion were not accomplished and the war were settled by a negotiated peace, at the conclusion of a drive to the Channel, can there be any doubt that Germany would have emerged triumphant? The sea-power enthusiasts stress the fact that a million square miles of German colonies lay in Allied hands as a result of control of the sea; but in a negotiated peace one square mile of northern France or Venetia would have been worth more for trading across the green table than ten thousand square miles of African jungle.

Briefly, then, while the control of the sea made the entry of the United States decisive, it is important to realize that, if the Germans had not committed the stupendous blunder of bringing the United States into the conflict, they would have won in the face of sea-power, and won overwhelmingly. And not even Tirpitz would have claimed that the German army was ‘the projectile of the navy.’ The situation makes an interesting parallel with the Napoleonic era. In 1811, England, in her struggle with Napoleon, as Mahan says, ‘touched the verge of ruin,’ and it was Napoleon’s ill-founded contempt for Spain, and particularly for Russia, which broke him just when he had almost reduced England, despite her control of the sea.


In order to appreciate why land-power came very near beating sea-power in the Great War, it is necessary to go back to first principles. What is the importance of sea-power? As Mahan has pointed out, this means control of the ‘illimitable highways’ of the world—in brief, of communications.

In Napoleon’s day, and of course during the centuries before, ocean highways were cheaper, easier, and safer than land highways. Roads were notoriously few and bad, even in the heart of civilization. In our day, however, communications by land are enormously improved. In addition to the military roads that were built in Europe as a consequence of Napoleon’s campaigns, there has arisen the vast system of railroads. In turn, the military road originally laid for marching troops became an invaluable supplement to the railroads, by means of the still later invention of the gasoline engine and motor-transport. It is true that sea-travel has also improved, but the old superiority of sea communications as against land communications has sharply declined. For instance, a route by rail from Hamburg to Bagdad has obvious advantages, for either commercial or military purposes, over the route from London to Bagdad by water.

Again, it is essential to understand that the importance of sea communications depends on the positions of the belligerents in relation to their resources. Repeatedly Mahan emphasizes the enormous value of interior lines. Sea communications usually represent exterior lines; but those exterior lines, when controlled by a sea-power, may come between the enemy and its necessities. In that case, control of the exterior lines more than offsets the advantage of the blockaded power in interior lines. If, however, a land-power to be so well organized in its resources as to be self-sufficient, and has developed a system of interior communications, it will lose its commerce and its colonies, but it may wage war successfully in the teeth of sea-power. Thus the Central Powers, in spite of their dependence on the rest of the world for certain raw materials, were on the whole so well prepared to stand alone that they were able to keep the initiative for four years. Moreover, they were able by conquest to make up for certain deficiencies in natural resources: as, for example, the iron and coal deposits of Belgium and Northern France, and money and food from every conquered province. Indeed, as to the vital question of food, vastly more might have been gained by conquest, had it not been for the wanton destruction that laid waste the fields of Poland, Galicia, and Roumania.

As to interior lines of communication, it is hardly necessary to point out the system of transport by rail and road which made it possible for the German High Command to strike a sledge-hammer blow, first on one front and then on another, with a celerity and a concentration of energy impossible to the Allies, whose communications were the exterior lines of the sea.

But these are merely the old factors which Mahan has discussed in his analysis of sea-power in history. In this war there have appeared two new factors which have already weakened sea-power in its very element, and threaten to weaken it very seriously in the future. In June, 1914, Admiral Sir Percy Scott wrote a letter to the Times in which he ventured the opinion that the submarine and the airplane had made surface navies obsolete. The test of the war proved that that prophecy had not yet come true; but Scott’s professional attainments are too well known to warrant treating that prophecy with ridicule. In a recent statement he declared that, if Germany had had two hundred submarines at the beginning of the war, she would have put an end to Britain’s sea-power and won the war at the very outset.

The submarine has, indeed, proved too slow to dispatch surface craft as readily as Scott expected; but it has proved to be the most powerful weapon yet devised for a naval power on the defensive. It is an ideal blockade-runner. Aided by mines, it has also held the blockading fleet hundreds of miles off the German coast and seriously threatened the very existence of the blockade. It is the deadliest commerce-destroyer ever invented. From the revelations of Captain Perseus we have learned that Germany never had more than one hundred and forty-nine completed submarines, and that no more than twenty or thirty were ever on the warpath at any one time. Indeed, the capacity for trouble that lies in a single one of these under-water craft raises the question whether it is even possible for any one nation in the future to claim control of the sea, especially as the submarine is now only in its infancy.

Surface sea-power is threatened, not only by a line of operation beneath the surface, but also by the line above the surface—the air. The air knows no islands, or ‘splendid isolation.’ The insular position of England has not rendered her immune from attack in this war, as it did in the days of Nelson and the centuries before. London and other English cities have been bombed on moonlight nights as regularly as Nancy and Dunkirk. Suppose Germany had begun the war with 100,000 fighting planes? And the airplane, even more than the submarine, is in its infancy, with an even greater range of development before it. In 1914 planes carried one or two passengers; at the end of four years Caproni is turning out a machine that will carry a hundred. The first transatlantic flight is not far in the future. Already the air is the highway of the messenger and the raider; in the future it may become the road of commerce and invasion. If the sea has held its importance in the past because it was the ‘illimitable highway’ of the world, how much more aptly does that phrase apply to the air?

In brief, the important point to be borne in mind is that the significance of sea-power in the past, present, or future is communications; and the need of communications by sea is the sole measure of the value of sea-power to any belligerent nation. For the Allies in this war sea-power was a matter of life or death, but for the Central Powers it was not essential. And for the Allies, sea-power and land-power were mutually dependent. One cannot be separated from the other with the title of ‘winner of the war.’

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Moreover, even the sum of land-power and sea-power in this war does not complete the equation. A third force deserves to stand beside army and navy as a factor of success—namely, propaganda. One of the great lessons of the French Revolution is that there is no explosive so terrible as an idea; and no historian of the present war can afford to overlook the tremendous driving force of the written and spoken word upon the peoples involved.

The fundamental aim of warfare is to destroy the enemy’s will to fight, or morale. The usual method is to destroy his powers of resistance by crushing his armed forces and by starving him into surrender. But a nation actually without an army and navy may, as Spain did in 1808, fight a desperate guerilla warfare against the invader, preferring extermination to surrender, and winning in the end—winning by sheer morale. On the other hand, we have the spectacle of Germany, while still uninvaded, while still in possession of huge tracts of enemy territory and of a still powerful army and navy, suddenly collapsing and accepting terms appropriate to a nation beaten prostrate and helpless. Clearly the morale was gone, and it was gone most conspicuously in the nation’s behind the lines. Undoubtedly a large share of this decay of morale was due to the growing victories of Foch and the failure of the submarine campaign; but a nation with the fighting spirit of Spain in 1808, or even with that of Germany in 1914, would have held out in spite of these things for many months. Clearly the German people had ceased to believe in their war and were only too glad to quit; and it was precisely to this end that the utterances of Lloyd George and Woodrow Wilson were aimed.

It is not possible within the limits of this article to do more than suggest the great part played by propaganda in this war. Two fanatics, — or scoundrels, — introduced by Germany into Russia, have done more to make Russia impotent than the armies and genius of Hindenburg and Mackensen combined. Propaganda in Italy led directly to one of the greatest military disasters of the war, — Caporetto, — and very nearly put her out of the war also. On our side, who shall estimate the value of the unified spirit of the United States in supporting the war, a spirit which surprised even ourselves, and was due largely to the campaign of the speech, the poster, the popular weekly, and the moving picture? Who has reckoned the effect of Woodrow Wilson’s leadership in keeping the radical elements of France and England behind the war at a time when they distrusted their own national leaders? What of the oppressed peoples of Austria-Hungary, who came to know that England and America stood openly for ‘self-determination’ and a ‘world made safe for democracy,’ and that the story of their own fighting in ‘defense of their fatherland’ was a lie made in Germany?

Bulgaria was the first to leave the sinking ship and scuttle it as she went. Bulgaria was not organized for war as Germany was, and she was invariably left out in the cold in the matter of dividing the plunder. Consequently she felt the blockade much more keenly than Germany. This was undoubtedly one reason of her collapse; but if she had been fighting the Turks for independence, as in the early days, such hardships as were suffered would have counted little. A recent analysis by an observer in Bulgaria gives too important elements besides the blockade in braking down the fighting spirit of the Bulgarian troops. One was the humanity of the British against whom they fought at Salonika, which led them to feel that those who had once been their friends could still be counted on to do them justice. The second is expressed as follows: —

‘President Wilson’s attitude had still greater influence. Although his speeches were reported to the country very inadequately, enough got out to convince the people that he favors a settlement on the lines of self-determination and of equal rights for the small and weak with the big and strong. They said, “If he will ask the Macedonians themselves what they want, our object is gained. We need shed no more blood.” For their impression is strong that the Peace Congress will be very much influenced by President Wilson’s views.’

The amazing rout of the Bulgarians from impregnable positions in Macedonia is singularly like that of the Italians as Caporetto, and according to the foregoing testimony, is to be explained in much the same way. In the case of Bulgaria, the rout involved the withdrawal of the nation from the war—a defection which was fatal to both Turkey and Austria, and, ultimately, to Germany.

Thus, the elements of victory develop a greater and greater complexity. Sea-power and land-power have combined mightily to achieve the prize; to these two we must add this other great force, — an ‘imponderable,’ — which deserves to rank among the weapons of war, as it has never done before in history, and which may acquire for the future historian an even greater significance than we can see to-day. At all events, this is not the time to announce that any single one of these forces ‘won the war,’ especially that force which essential as it was to the Allied cause, was compelled to play throughout the war a part almost wholly defensive.

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