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1 The choice of the principal roads, if the two countries are connected by more roads than we wish to fortify.
2 Whether the fortresses are to be placed on the frontier only, or spread over the country.
Amongst a number of great roads leading from the enemys country into ours, we should first of all fortify
that which leads most directly to the heart of our dominions, or that which, traversing fertile provinces, or
running parallel to navigable rivers, facilitates the enemys undertaking, and then we may rest secure.
The assailant then encounters these works, or should he resolve to pass them by, he will naturally offer
a favourable opportunity for operations against his flank.
We turn now to the second question -- Whether the fortresses should be placed on the frontier, or distributed over the country? In the first place, we must observe, that, as regards small states, this question is superfluous, for what are called strategic frontiers coincide, in their case, nearly with the whole country. The larger the state is supposed to be in the consideration of this question, the plainer appears the necessity for its being answered.
The most natural answer is -- that fortresses belong to the frontiers, for they are to defend the state, and the state is defended as long as the frontiers are defended. This argument may be valid in the abstract, but the following considerations will show that it is subject to very many modifications.
Every defence which is calculated chiefly on foreign assistance lays great value on gaining time; it is not
a vigorous counterstroke, but a blow proceeding, in which the chief gain consists more in delay than in
any weakening of the enemy which is effected. But now it lies in the nature of the thing that, supposing
all other circumstances alike, fortresses which are spread over the whole country, and include between
them a very considerable area of territory, will take longer to capture than those squeezed together in a
close line on the frontier. Further, in all cases in which the object is to overcome the enemy through the
length of his communications, and the difficulty of his existence, therefore in countries which can chiefly
reckon on this kind of reaction, it would be a complete contradiction to have the defensive preparations
of this kind only on the frontier. Lastly, let us also remember that, if circumstances will in any way allow
of it, the fortification of the capital is a main point; that according to our principles the chief towns and
places of commerce in the provinces demand it otherwise; that rivers passing through the country, mountains,
and other irregular features of ground, afford advantages for new lines of defence; that many towns, through
their strong natural situation, invite fortification; moreover, that certain accessories of war, such as manufactories
of arms, etc., are better placed in the interior of the country than on the frontier, and their value well
entitles them to the protection of works of fortification; then we see that there is always more or less
occasion for the construction of fortresses in the interior of a country; on this account we are of opinion,
that although states which possess a great number of fortresses are right in placing the greater number
on the frontier, still it would be a great mistake if the interior of the country was left entirely destitute of