Instructions for the Government of Armies of the United States in the Field

Art. 14. Military necessity, as understood by modern civilized nations,
consists in the necessity of those measures which are indispensable for
securing the ends of the war, and which are lawful according to the modern
law and usages of war.

Art. 15. Military necessity admits of all direct destruction of life or
limb of armed enemies, and of other persons whose destruction is
incidentally unavoidable in the armed contests of the war; it allows of the
capturing of every armed enemy, and every enemy of importance to the
hostile government, or of peculiar danger to the captor; it allows of all
destruction of property, and obstruction of the ways and channels of
traffic, travel, or communication, and of all withholding of sustenance or
means of life from the enemy; of the appropriation of whatever an enemy’s
country affords necessary for the subsistence and safety of the army, and
of such deception as does not involve the breaking of good faith either
positively pledged, regarding agreements entered into during the war, or
supposed by the modern law of war to exist. Men who take up arms against
one another in public war do not cease on this account to be moral beings,
responsible to one another and to God.

Art. 16. Military necessity does not admit of cruelty – that is, the
infliction of suffering for the sake of suffering or for revenge, nor of
maiming or wounding except in fight, nor of torture to extort confessions.
It does not admit of the use of poison in any way, nor of the wanton
devastation of a district. It admits of deception, but disclaims acts of
perfidy; and, in general, military necessity does not include any act of
hostility which makes the return to peace unnecessarily difficult.

Art. 17. War is not carried on by arms alone. It is lawful to starve the
hostile belligerent, armed or unarmed, so that it leads to the speedier
subjection of the enemy.

Art. 18. When a commander of a besieged place expels the noncombatants, in
order to lessen the number of those who consume his stock of provisions, it
is lawful, though an extreme measure, to drive them back, so as to hasten
on the surrender.

Art. 19. Commanders, whenever admissible, inform the enemy of their
intention to bombard a place, so that the noncombatants, and especially the
women and children, may be removed before the bombardment commences. But it
is no infraction of the common law of war to omit thus to inform the enemy.
Surprise may be a necessity.

Art. 20. Public war is a state of armed hostility between sovereign nations
or governments. It is a law and requisite of civilized existence that men
live in political, continuous societies, forming organized units, called
states or nations, whose constituents bear, enjoy, suffer, advance and
retrograde together, in peace and in war.

Art. 21. The citizen or native of a hostile country is thus an enemy, as
one of the constituents of the hostile state or nation, and as such is
subjected to the hardships of the war.

Art. 22. Nevertheless, as civilization has advanced during the last
centuries, so has likewise steadily advanced, especially in war on land,
the distinction between the private individual belonging to a hostile
country and the hostile country itself, with its men in arms. The principle
has been more and more acknowledged that the unarmed citizen is to be
spared in person, property, and honor as much as the exigencies of war will
admit.

Art. 23. Private citizens are no longer murdered, enslaved, or carried off
to distant parts, and the inoffensive individual is as little disturbed in
his private relations as the commander of the hostile troops can afford to
grant in the overruling demands of a vigorous war.

Art. 24. The almost universal rule in remote times was, and continues to be
with barbarous armies, that the private individual of the hostile country
is destined to suffer every privation of liberty and protection, and every
disruption of family ties. Protection was, and still is with uncivilized
people, the exception.

Art. 25. In modern regular wars of the Europeans, and their descendants in
other portions of the globe, protection of the inoffensive citizen of the
hostile country is the rule; privation and disturbance of private relations
are the exceptions.

Art. 26. Commanding generals may cause the magistrates and civil officers
of the hostile country to take the oath of temporary allegiance or an oath
of fidelity to their own victorious government or rulers, and they may
expel everyone who declines to do so. But whether they do so or not, the
people and their civil officers owe strict obedience to them as long as
they hold sway over the district or country, at the peril of their lives.

Art. 27. The law of war can no more wholly dispense with retaliation than
can the law of nations, of which it is a branch. Yet civilized nations
acknowledge retaliation as the sternest feature of war. A reckless enemy
often leaves to his opponent no other means of securing himself against the
repetition of barbarous outrage

Art. 28. Retaliation will, therefore, never be resorted to as a measure of
mere revenge, but only as a means of protective retribution, and moreover,
cautiously and unavoidably; that is to say, retaliation shall only be
resorted to after careful inquiry into the real occurrence, and the
character of the misdeeds that may demand retribution.

Unjust or inconsiderate retaliation removes the belligerents farther and
farther from the mitigating rules of regular war, and by rapid steps leads
them nearer to the internecine wars of savages.

Art. 29. Modern times are distinguished from earlier ages by the existence,
at one and the same time, of many nations and great governments related to
one another in close intercourse.

Peace is their normal condition; war is the exception. The ultimate object
of all modern war is a renewed state of peace.

The more vigorously wars are pursued, the better it is for humanity. Sharp
wars are brief.

Art. 30. Ever since the formation and coexistence of modern nations, and
ever since wars have become great national wars, war has come to be
acknowledged not to be its own end, but the means to obtain great ends of
state, or to consist in defense against wrong; and no conventional
restriction of the modes adopted to injure the enemy is any longer
admitted; but the law of war imposes many limitations and restrictions on
principles of justice, faith, and honor.