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.