animals, that because the abundance in which they are found is a
product of human labour, they may be used, destroyed, and consumed
by man; so it seems that it may be said of the sovereign, as the
supreme power in the state, that he has the right to lead his
subjects, as being for the most part productions of his own, to war,
as if it were to the chase, and even to march them to the field of
battle, as if it were on a pleasure excursion.

  This principle of right may be supposed to float dimly before the
mind of the monarch, and it certainly holds true at least of the lower
animals which may become the property of man. But such a principle
will not at all apply to men, especially when viewed as citizens who
must be regarded as members of the state, with a share in the
legislation, and not merely as means for others but as ends in
themselves. As such they must give their free consent, through their
representatives, not only to the carrying on of war generally, but
to every separate declaration of war; and it is only under this
limiting condition that the state has a right to demand their services
in undertakings so full of danger.

  We would therefore deduce this right rather from the duty of the
sovereign to the people than conversely. Under this relation, the
people must be regarded as having given their sanction; and, having
the right of voting, they may be considered, although thus passive
in reference to themselves individually, to be active in so far as
they represent the sovereignty itself.

              56. Right of Going to War in relation

                        to Hostile States.

  Viewed as in the state of nature, the right of nations to go to
war and to carry on hostilities is the legitimate way by which they
prosecute their rights by their own power when they regard
themselves as injured; and this is done because in that state the
method of a juridical process, although the only one proper to
settle such disputes, cannot be adopted.

  The threatening of war is to be distinguished from the active injury
of a first aggression, which again is distinguished from the general
outbreak of hostilities. A threat or menace may be given by the active
preparation of armaments, upon which a right of prevention (jus
praeventionis) is founded on the other side, or merely by the
formidable increase of the power of another state (potestas
tremenda) by acquisition of territory. Lesion of a less powerful
country may be involved merely in the condition of a more powerful
neighbour prior to any action at all; and in the state of nature an
attack under such circumstances would be warrantable. This
international relation is the foundation of the right of
equilibrium, or of the "balance of power," among all the states that
are in active contiguity to each other.

  The right to go to war is constituted by any overt act of injury.
This includes any arbitrary retaliation or act of reprisal
(retorsio) as a satisfaction taken by one people for an offence
committed by another, without any attempt being made to obtain
reparation in a peaceful way. Such an act of retaliation would be
similar in kind to an outbreak of hostilities without a previous
declaration of war. For if there is to be any right at all during
the state of war, something analogous to a contract must be assumed,
involving acceptance on the side of the declaration on the other,
and amounting to the fact that they both will to seek their right in
this way.

                 57. Right during War.

  The determination of what constitutes right in war, is the most
difficult problem of the right of nations and international law. It is
very difficult even to form a conception of such a right, or to
think of any law in this lawless state without falling into a
contradiction. Inter arma silent leges.* It must then be just the
right to carry on war according to such principles as render it always
still possible to pass out of that natural condition of the states
in their external relations to each other, and to enter into a
condition of right.

  *["In the midst of arms the laws are silent." Cicero.]

  No war of independent states against each other can rightly be a war
of punishment (bellum punitivum). For punishment is only in place
under the relation of a superior (imperantis) to a subject (subditum);
and this is not the relation of the states to one another. Neither can
an international war be "a war of extermination" (bellum
internicinum), nor even "a war of subjugation" (bellum subjugatorium);
for this would issue in the moral extinction of a state by its
people being either fused into one mass with the conquering state,
or being reduced to slavery. Not that this necessary means of
attaining to a condition of peace is itself contradictory to the right
of a state; but because the idea of the right of nations includes
merely the conception of an antagonism that is in accordance with
principles of external freedom, in order that the state may maintain
what is properly its own, but not that it may acquire a condition
which, from the aggrandizement of its power, might become
threatening to other states.

  Defensive measures and means of all kinds are allowable to a state
that is forced to war, except such as by their use would make the
subjects using them unfit to be citizens; for the state would thus
make itself unfit to be regarded as a person capable of
participating in equal rights in the international relations according