truncated method of war on which profitable study can be founded.

The primary method, then, in which we use victory or preponderance at sea
and bring it to bear on the enemy's population to secure peace, is by the
capture or destruction of the enemy's property, whether public or private.
But in comparing the process with the analogous occupation of territory and
the levying of contributions and requisitions we have to observe a marked
difference. Both processes are what may be called economic pressure. But
ashore the economic pressure can only be exerted as the consequence of
victory or acquired domination by military success. At sea the process
begins at once. Indeed, more often than not, the first act of hostility in
maritime wars has been the capture of private property at sea. In a sense
this is also true ashore. The first step of an invader after crossing the
frontier will be to control to a less or greater extent such private
property as he is able to use for his purposes. But such interference with
private property is essentially a military act, and does not belong to the
secondary phase of economic pressure. At sea it does, and the reason why
this should be so lies in certain fundamental differences between land and
sea warfare which are implicit in the communication theory of naval war.

To elucidate the point, it must be repeated that maritime communications,
which are the root of the idea of command of the sea, are not analogous to
military communications in the ordinary use of the term. Military
communications refer solely to the army's lines of supply and retreat.
Maritime communications have a wider meaning. Though in effect embracing
the lines of fleet supply, they correspond in strategical values not to
military lines of supply, but to those internal lines of communication by
which the flow of national life is maintained ashore. Consequently maritime
communications are on a wholly different footing from land communications.
At sea the communications are, for the most part, common to both