In a war which is both naval and continental, as in the present war, command of the sea means much more than the power to deny the gain and comfort of sea supplies. The side that is defeated at sea, or avoids fighting for fear of defeat, may lose not only everything which can come to it directly or indirectly from the use of ships, but will suffer from the added disadvantage that a military use can be made of sea communications in the enemy’s possession. The side that commands the sea can carry on its ocean traffic, and supply not only its civil population but its armies and its fleets from abroad. It can ally itself with continental nations and send its military forces away in ships and land them in friendly ports. It can prevent the sea invasion of its own, of its allies’ territory, and of its colonial possessions. It can stop not only the enemy’s own sea trade, but all neutral sea trade that directly or indirectly can benefit him, so that he is cut off from all supplies, whether raw material, food, or manufacture, not produced in his own territories or in those with which he has land communications. If the sea force of the side possessing command includes means of engaging stationary defences with success, and removing passive sea defences from the approaches to the enemy’s coast and harbours, then it can even beat down the enemy’s coast protection and invade him directly. The nation with sea command, then, threatens its opponents with attack by land at every point and, pending its development, can to the extent to which the enemy is dependent on overseas traffic for the necessaries of life, or for the maintenance of his armies at full fighting strength, subject him to all the rigour of siege. The command of the sea which makes the exercise of these menaces possible, is, as we have seen, the fruit of victory over the enemy’s armed forces. But if that enemy is weaker and follows at sea the course which, as we have seen, an army inferior on land must adopt, viz., declines battle and withdraws his fleet behind defences to postpone it, he thereby to a great extent surrenders the sea command to the stronger. And if the stronger knows his business, he at once uses this command to subject his opponent to the economic disadvantages set out above. Siege by sea, then, like siege on land, may be the consequence of, but is always the alternative to, victorious battle in bringing about a decision. For while victorious battle robs the defeated nation of any possibility of warding off further attack by force, siege undermines the will and resolution of the civil population to endure, and thus calls forces into existence which will compel the enemy’s government to surrender.