He was wrong then and he is wrong now. It was an error to think of sea-power _only_ in terms of battleships. It is a still greater error to suppose that sea-power can exist in any useful form _unless_ based on battleships in overwhelming strength. It is true that the German submarines did for a period so threaten the world’s shipping as to make it possible that the overwhelming military resources of the Allies might never be brought to bear against the full strength of the German line in France. It is also true that they have added years to the duration of the war, millions and millions to its cost, and have brought us to straits that are hard to bear. They were truly Germany’s most powerful defence, the only useful form of sea force for her. But it is, nevertheless, quite impossible that the submarine can give to Germany any of the direct advantages which the command of the sea confers. These simple truths will come home convincingly to us if we suppose for a minute that, at the only encounter in which the battle fleets met, it had been the German Fleet that was victorious. Had Scheer and Von Hipper met Beatty and Jellicoe in a fair, well-fought-out action, and sunk or captured the greater part of the British Fleet so that but a crippled remnant could struggle back to harbour--as little left of the mighty British armada as survived of Villeneuve’s and Gravina’s forces after Trafalgar--would it ever have been necessary for Germany to have challenged the forbearance of the world by reckless and piratical attacks on peaceful shipping? Quite obviously not. For with her battle-cruisers patrolling unchallenged in the Channel, the North Sea, and the Atlantic, with all her destroyers and light cruisers working under their protection, no British merchantman could have cleared or entered any British port, no neutral could have passed the blockading lines. British submarines might, indeed, have held up German shipping--but we should have lost the use of merchant shipping ourselves. Our armies would have been cut off from their overseas base, our fighting Allies would have been robbed of the food and material now reaching them from North and South America and the British Dominions, and the civil population of England, Scotland, Ireland, and Wales, would have been threatened by immediate invasion or by not very far distant famine. And this is so because command of the sea is conditioned by a superior battleship strength, and can only be exercised by surface craft which cannot be driven off the sea.