State it has some value. Consequently by denying an enemy this means of
passage we check the movement of his national life at sea in the same kind
of way that we check it on land by occupying his territory. So far the
analogy holds good, but no further.

So much for the positive value which the sea has in national life. It has
also a negative value. For not only is it a means of communication, but,
unlike the means of communication ashore, it is also a barrier. By winning
command of the sea we remove that barrier from our own path, thereby
placing ourselves in position to exert direct military pressure upon the
national life of our enemy ashore, while at the same time we solidify it
against him and prevent his exerting direct military pressure upon
ourselves.

Command of the sea, therefore, means nothing but the control of maritime
communications, whether for commercial or military purposes. The object of
naval warfare is the control of communications, and not, as in land
warfare, the conquest of territory. The difference is fundamental. True, it
is rightly said that strategy ashore is mainly a question of
communications, but they are communications in another sense. The phrase
refers to the communications of the army alone, and not to the wider
communications which are part of the life of the nation.

But on land also there are communications of a kind which are essential to
national life--the internal communications which connect the points of
distribution. Here again we touch an analogy between the two kinds of war.
Land warfare, as the most devoted adherents of the modern view admit,
cannot attain its end by military victories alone. The destruction of your
enemy's forces will not avail for certain unless you have in reserve
sufficient force to complete the occupation of his inland communications