This truth is so obvious that it would scarcely be worth mentioning were it not for the constant recurrence of such phrases as:  “If England were to lose command of the sea, it would be all over with her.”  The fallacy of the idea is that it ignores the power of the strategical defensive.  It assumes that if in the face of some extraordinary hostile coalition or through some extraordinary mischance we found ourselves without sufficient strength to keep the command, we should therefore be too weak to prevent the enemy getting it—­a negation of the whole theory of war, which at least requires further support than it ever receives.

And not only is this assumption a negation of theory; it is a negation both of practical experience and of the expressed opinion of our greatest masters.  We ourselves have used the defensive at sea with success, as under William the Third and in the War of American Independence, while in our long wars with France she habitually used it in such a way that sometimes for years, though we had a substantial preponderance, we could not get command, and for years were unable to carry out our war plan without serious interruption from her fleet.

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.