So far from the defensive being a negligible factor at sea, or even the mere pestilent heresy it is generally represented, it is of course inherent in all war, and, as we have seen, the paramount questions of strategy both at sea and on land turn on the relative possibilities of offensive and defensive, and upon the relative proportions in which each should enter into our plan of war. At sea the most powerful and aggressively-minded belligerent can no more avoid his alternating periods of defence, which result from inevitable arrests of offensive action, than they can be avoided on land. The defensive, then, has to be considered; but before we are in a position to do so with profit, we have to proceed with our analysis of the phrase, "Command of the Sea," and ascertain exactly what it is we mean by it in war. In the first place, "Command of the Sea" is not identical in its strategical conditions with the conquest of territory. You cannot argue from the one to the other, as has been too commonly done. Such phrases as the "Conquest of water territory" and "Making the enemy's coast our frontier" had their use and meaning in the mouths of those who framed them, but they are really little but rhetorical expressions founded on false analogy, and false analogy is not a secure basis for a theory of war. The analogy is false for two reasons, both of which enter materially into the conduct of naval war. You cannot conquer sea because it is not susceptible of ownership, at least outside territorial waters. You cannot, as lawyers say, "reduce it into possession," because you cannot exclude neutrals from it as you can from territory you conquer. In the second place, you cannot subsist your armed force upon it as you can upon enemy's territory. Clearly, then, to make deductions from an assumption that command of the sea is analogous to conquest of territory is unscientific, and certain to lead to error. The only safe method is to inquire what it is we can secure for ourselves, and what it is we can deny the enemy by command of the sea. Now, if we exclude fishery rights, which are irrelevant to the present matter, the only right we or our enemy can have on the sea is the right of passage; in other words, the only positive value which the high seas have for national life is as a means of communication. For the active life of a nation such means may stand for much or it may stand for little, but to every maritime 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.