absence of such an army proved the defensive aims of the British Empire before the war. World domination could only be secured by the combination of a dominant army with a dominant navy, and hence the significance of the German naval programme designed at least to prevent the counteraction of one by the other. But while a supreme navy suffices to protect an island empire, it does not suffice to defend continental states; and the importance of British sea-power was that it gave us and other oversea peoples the liberty to take as much or as little part as we chose in a war to defend states that were threatened on land. The existence of that facility did not determine the extent to which it might be used by ourselves or by allies. That would depend upon the size of the armies we raised and the labour we spent upon their equipment; and we might have restricted our expeditionary forces to the numbers we sent under Marlborough against Louis XIV or under Wellington against Napoleon. But we could not have sent any without the command of the sea; and the essence of that command is that, firstly, it prevented the enemy from using his armies to invade our shores, and, secondly, it enabled us to send whatever forces we liked to whatever sphere of operations was not commanded by the enemy's armies. Philip II had demonstrated once for all the emptiness of the invasion scare when he sent a superb military expedition, the Spanish Armada, across a sea which he did not command; and the efforts of German submarines failed to affect the transport of our own and our Allies' troops or seriously to impede their communications.