A state attacked by another which renews an old claim rarely yields it
without a war: it prefers to defend its territory, as is always more
honorable. But it may be advantageous to take the offensive, instead of
awaiting the attack on the frontiers.

There are often advantages in a war of invasion: there are also
advantages in awaiting the enemy upon one's own soil. A power with no
internal dissensions, and under no apprehension of an attack by a third
party, will always find it advantageous to carry the war upon hostile
soil. This course will spare its territory from devastation, carry on
the war at the expense of the enemy, excite the ardor of its soldiers,
and depress the spirits of the adversary. Nevertheless, in a purely
military sense, it is certain that an army operating in its own
territory, upon a theater of which all the natural and artificial
features are well known, where all movements are aided by a knowledge of
the country, by the favor of the citizens, and the aid of the
constituted authorities, possesses great advantages.

These plain truths have their application in all descriptions of war;
but, if the principles of strategy are always the same, it is different
with the political part of war, which is modified by the tone of
communities, by localities, and by the characters of men at the head of
states and armies. The fact of these modifications has been used to
prove that war knows no rules. Military science rests upon principles
which can never be safely violated in the presence of an active and
skillful enemy, while the moral and political part of war presents these
variations. Plans of operations are made as circumstances may demand: to
execute these plans, the great principles of war must be observed.

For instance, the plan of a war against France, Austria, or Russia would