en apart from direct colonization, to
bring territorial occupation in its train. The origin and history of the
British rule in India is a signal illustration of this tendency. There
are other causes of territorial expansion across the seas, as Admiral
Mahan has pointed out in his latest work on _Naval Strategy_, but it is
a rule which admits of no exceptions that territorial possessions across
the seas, however they may have been acquired, compel the Power which
holds them to develop a navy which, in the last resort, must be capable
of defending them. It was not, indeed, the needs of maritime commerce
which induced the United States to acquire Puerto Rico and the
Philippines. Their acquisition was, as it were, a by-product of
victorious sea power. But the vast expansion of the United States Navy
which the last dozen years have witnessed is the direct result and the
logical consequence of their acquisition.

Applying these principles to the defence of the British Empire we see at
once that the command of the sea, in the sense already defined, is
essential to its successful prosecution. The case is not merely
exceptional, it is absolutely unique. The British Isles might recover
from the effects of a successful invasion, as other countries have done
in like case. But the destruction of their maritime commerce would ruin
them irretrievably, even if no invasion were undertaken. Half the
maritime commerce of the world is carried on under the British flag. The
whole of that commerce would be suppressed if an enemy once secured the
command of the sea. The British Isles would be starved out in a few
weeks. Whether an enemy so situated would decide to invade or
invest--that is, so to impede our commerce that only an insignificant
fraction of it could by evasion reach our ports--is a question not so
much of strategy as of the economics of warfare. But really it hardly
matters a pin which he decided to do. We should have to submit in either
case. What would happen to our Dominions, Dependencies, and Colonies is
plain. Those which are defenceless the enemy would seize if he thought
it worth his while. In the case supposed they could obtain no military
assistance from the mother-country. But those which could defend
themselves he would have to overcome, if he could, by fighting. The
great Dominions of the Empire would not fall into an enemy's lap merely
because he had compelled the United Kingdom to sue for peace. To subdue
them by f