20. Declaration of War Required

a. Treaty Provision.

The Contracting Powers recognize that hostilities between themselves must not commence without previous and explicit warning, in the form either of a reasoned declaration of war or of an ultimatum with conditional declaration of war. (H. III, art. 1.)

b. Surprise Still Possible. Nothing in the foregoing rule requires that any particular length of time shall elapse between a declaration of war and the commencement of hostilities.

21. Notification to Neutrals

The existence of a state of war must be notified to the neutral Powers without delay, and shall not take effect in regard to them until after the receipt of a notification, which may, however, be given by telegraph. Neutral Powers, nevertheless, cannot rely on the absence of notification if it is clearly established that they were in fact aware of the existence of a state of war. (H. III, art. 2.)

22. When Articles of Hague Convention No. III Effective Between Parties Article I of the present Convention shall take effect in case of war between two or more of the Contracting Powers.

Article II is binding as between a belligerent Power which is a party to the Convention and neutral Powers which are also parties to the Convention. (H. III, art. 3.)

23. Present Effect of Foregoing Rules

The Charter of the United Nations makes illegal the threat or use of force contrary to the purpose of the United Nations. It requires members of the organization to bring about by peaceful means adjustment or settlement of international disputes or situations which might lead to a breach of the peace. However, a nonmember nation or a member nation which violates these provisions of the Charter commits a further breach of international law by commencing hostilities without a declaration of war or a conditional ultimatum as required by the foregoing articles of Hague Convention No. III. Conversely, a State which resorts to war in violation of the Charter will not render its acts of aggression or breach of the peace any the less unlawful by formally declaring war.

24. Constitutional Provision

Article 1, section 8, clause 11, of the United States Constitution provides that "The Congress shall have power * * * to declare War." The law of war may, however, be applicable to an international conflict, notwithstanding the absence of a declaration by the Congress. (See pars. 8 and 9, concerning the situations to which the law of war has application.)

25. Enemy Status of Civilians

Under the law of the United States, one of the consequences of the existence of a condition of war between two States is that every national of the one State becomes an enemy of every national of the other. However, it is a generally recognized rule of international law that civilians must not be made the object of attack directed exclusively against them.

26. Effect on Enemy Aliens

Enemy aliens located or resident in United States territory are not necessarily made prisoners or interned en masse on the breaking out of hostilities. Such persons may be allowed to leave the United States if their departure is consistent with national interest (GC, art. 35; par. 274 herein). If the security of the United States makes it absolutely necessary, enemy aliens may be placed in assigned residence or internment (GC, art. 42; par. 281 herein). Measures of control are normally taken with respect to at least persons known to be active or reserve members of a hostile army, persons who would be liable to service in the enemy forces, and persons who it is expected would furnish information or other aid to a hostile State. (See ch. V, sec. IV, concerning the treatment of aliens in the territory of a party to the conflict.)

27. Expulsion

In modern practice at the outbreak of hostilities the expulsion of the citizens or subjects of the enemy is generally decreed from seaports, the area surrounding airbases, airports, and fortified places, areas of possible attack, and the actual or contemplated theaters of operation. When expulsion is decreed, the persons expelled should be given such reasonable notice, consistent with public safety, as will enable them to arrange for the collection, disposal, and removal of their goods and property and for the settlement of their personal affairs. Such persons do not, however, benefit from the provisions of Articles 41 through 45, GC (pars. 280-284).


28. Refusal of Quarter

It is especially forbidden * * * to declare that no quarter will be given. (HR, art. 23, par. (d).)

29. Injury Forbidden After Surrender

It is especially forbidden * * * to kill or wound an enemy who, having laid down his arms, or having no longer means of defense, has surrendered at discretion. (HR, art. 23, par. (c).)

30. Persons Descending by Parachute

The law of war does not prohibit firing upon paratroops or other persons who are or appear to be bound upon hostile missions while such persons are descending by parachute. Persons other than those mentioned in the preceding sentence who are descending by parachute from disabled aircraft may not be fired upon.

31. Assassination and Outlawry

HR provides:

It is especially forbidden * * * to kill or wound treacherously individuals belonging to the hostile nation or army. (HR, art. 23, par. (b).)

This article is construed as prohibiting assassination, proscription, or outlawry of an enemy, or putting a price upon an enemy's head, as well as offering a reward for an enemy "dead or alive". It does not, however, preclude attacks on individual soldiers or officers of the enemy whether in the zone of hostilities, occupied territory, or elsewhere.

32. Nationals Not To Be Compelled to Take Part in Operations Against Their Own Country

A belligerent is likewise forbidden to compel the nationals of the hostile party to take part in the operations of war directed against their own country, even if they were in the belligerent's service before the commencement of the war. (HR, art. 23, 2d par.)


33. Means of Injuring the Enemy Limited

a. Treaty Provision.

The right of belligerents to adopt means of injuring the enemy is not unlimited. (HR, art. 22.)

b. The means employed are definitely restricted by international declarations and conventions and by the laws and usages of war.

34. Employment of Arms Causing Unnecessary Injury

a. Treaty Provision.

It is especially forbidden * * * to employ arms, projectiles, or material calculated to cause unnecessary suffering. (HR, art. 23, par. (e).)

b. Interpretation. What weapons cause "unnecessary injury" can only be determined in light of the practice of States in refraining from the use of a given weapon because it is believed to have that effect. The prohibition certainly does not extend to the use of explosives contained in artillery projectiles, mines, rockets, or hand grenades. Usage has, however, established the illegality of the use of lances with barbed heads, irregular-shaped bullets, and projectiles filled with glass, the use of any substance on bullets that would tend unnecessarily to inflame a wound inflicted by them, and the scoring of the surface or the filing off of the ends of the hard cases of bullets.

35. Atomic Weapons

The use of explosive "atomic weapons," whether by air, sea, or land forces, cannot as such be regarded as violative of international law in the absence of any customary rule of international law or international convention restricting their employment.

36. Weapons Employing Fire

The use of weapons which employ fire, such as tracer ammunition, flamethrowers, napalm and other incendiary agents, against targets requiring their use is not violative of international law. They should not, however, be employed in such a way as to cause unnecessary suffering to individuals.

37. Poison

a. Treaty Provision.

It is especially forbidden * * * to employ poison or poisoned weapons. (HR, art. 23, par. (a).)

*b. Discussion of Rule. The foregoing rule prohibits the use in war of poison or poisoned weapons against human beings. Restrictions on the use of herbicides as well as treaty provisions concerning chemical and bacteriological warfare are discussed in paragraph 38.

*38. Chemical and Bacteriological Warfare

a. Treaty Provision. Whereas the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices, has been justly condemmed by the general opinion of the civilized world; and

Whereas the prohibition of such use has been declared in Treaties to which the majority of Powers of the world are Parties; and

To the end that this prohibition shall be universally accepted as a part of International Law, binding alike the conscience and the practice of nations:

***the High Contracting Parties, so fas as they are not already Parties to Treaties prohibiting such use, accept this prohibition, agree to extend this prohibition to the use of bacteriological methods of warfare and agree to be bound as between themselves according to the terms of this declaration. (Geneva Protocol of 1925.)

b. United States Reservation to the Geneva Protocol of 1925. [T]he said Protocol shall cease to be binding on the government of the United States with respect to the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials, or devices, in regard to an enemy State or any of its allies fails to respect the prohibitions laid down in the Protocol.

c. Renunciation of Certain Uses in War of Chemical Herbicides and Riot Control Agents. The United States renounces, as a matter of national policy, first use of herbicides in war except use, under regulations applicable to their domestic use, for control of vegetation within US bases and installations or around their immediate defensive perimeters, and first use of riot control agents in war except in defensive military modes to save lives such as:

(1) Use of riot control agents in riot control situations in areas under direct and distinct US military control, to include controlling rioting prisoners of war.

(2) Use of riot control agents in situations in which civilians are used to mask or screen attacks and civilian casualities can be reduced or avoided.

(3) Use of riot control agents in rescue missions in remotely isolated areas, of downed aircrews and passengers, and escaping prisoners.

(4) Use of riot control agents in rear echelon areas outside the zone of immediate combat to protect convoys from civil disturbances, terrorists and paramilitary organizations.








NOW, THREREFORE, by virtue of the authority vested me as President of the United States of America by the Constitution and laws of the United States and as Commander-in-Chief of the Armed Forces of the United States, it is hereby ordered as follows:

SECTION 1. The Secretary of Defense shall take all necessary measures to ensure that the use by the Armed Forces of the United States of any riot control agents and chemical herbicides in war is prohibited unless such use has Presidential approval, in advance.

SECTION 2. The Secretary of Defense shall prescribe the rules and regulations be deems necessary to ensure that the national policy herein announced shall be observed by the Armed Forces of the United States. (Exec. Order No. 11850, 40 Fed. Reg. 16187 (1975).)

d. Discussion. Although the language of the 1925 Geneva Protocol appears to ban unqualifiedly the use in war of the chemical weapons within the scope of its prohibition, reservations submitted by most of the Parties to the Protocol, including the United States, have, in effect, rendered the Protocol a prohibition only of the first use in war of materials within its scope. Therefore, the United States, like many other Parties, has reserved the right to use chemical weapons against a state if that state or any of its allies fails to respect the prohibitions of the Protocol.

The reservation of the United States does not, however, reserve the right to retaliate with bacteriological methols of warfare against a state if that state or any of its allies fails to respect the prohibitions of the Protocol. The prohibition concerning bacteriological methods of warfare which the United States has accepted under the Protocol, therefore, proscribes not only the initial but also any retaliatory use of bacteriological methods of warfare. In this connection, the United States considers bacteriological methods of warfare to include not only biological weapons but also toxins, which, although not living organisms and therefore susceptible of being characterized as chemical agents, are generally produced from biological agents. All toxins, however, regardless of the manner of production, are regarded by the United States as bacteriological methods of warfare within the meaning of the proscription of the Geneva Protocol of 1925.

Concerning chemical weapons, the United States considers the Geneva Protocol of 1925 as applying to both lethal and incapacitating chemical agents. Incapacitating agents are those producing symptoms that persist for hours or even days after exposure to the agent has terminated. It is the position of the United States that the Geneva Protocol of 1925 does not prohibit the use in war of either chemical herbicides or riot control agents, which are those agents of a type widely used by governments for law enforcement purposes because they produce, in all but the most unusual circumstances, merely transient effects that disappear within minutes after exposure to the agent has terminated. In this connection, however, the United States has unilaterally renounced, as a matter of national policy, certain uses in war of chemical herbicides and riot control agents (see Exec. Order No. 11850 above). The policy and provisions of Executive Order No. 11850 do not, however, prohibit or restrict the use of chemical herbicides or riot control agents by US armed forces either (1) as retaliation in kind during armed conflict or (2) in situations when the United States is not engaged in armed conflict. Any use in armed conflict of herbicides or riot control agents, however, requires Presidential approval in advance.

The use in war of smoke and incendiary materials is not prohibited or restricted by the Geneva Protocol of 1925.


*39. Bombardment of Undefended Places Forbidden

a. Treaty Provision. The attack or bombardment, by whatever means, of town, villages, dwellings, or buildings which are undefended is prohibited. (HR, art. 25.)

b. Interpretation. An undefended place, within the meaning of Article 25, HR, is any inhabited place near or in a zone where opposing armed forces are in contact which is open for occupation by an adverse party without resistance. In order to be considered as undefended, the following conditions should be fulfilled:

(1) Armed forces and all other combatants, as well as mobile weapons and mobile military equipment, must have been evacuated, or otherwise neutralized;

(2) no hostile use shall be made of fixed military installations or establishments;

(3) no acts of warfare shall be committed by the authorities or by the population; and,

(4) no activities in support of military operations chall be be undertaken.

The presence, in the place, of medical units, wounded and sick, and police forces retained for the sole purpose of maintaining law and order does not change the character of such an undefended place.

*40. Permissible Objects of Attack of Bombardment

a. Attacks Against the Civilian Population as Such Prohibited. Customary international law prohibits the launching of attacks (including bombardment) against either the civilian population as such or individual civilians as such.

b. Defended Places. Defended places, which are outside the scope of the proscription of Article 25, HR, are permissible objects of attack (including bombardment). In this context, defended places include--

(1) A fort or fortified place.

(2) A place that is occupied by a combatant military force or through which such a force is passing. The occupation of a place by medical units alone, however, is not sufficient to render it a permissible object of attack.

(3) A city or town surrounded by detached defense positions, if under the circumstances the city or town can be considered jointly with such defense positions as an indivisible whole.

c. Military Objectives. Military objectives--i.e., combatants, and those objects which by their nature, location, purpose, or use make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage--are permissible objects of attack (including bombardment). Military objectives include, for example, factories producing munitions and military supplies, military camps, warehouses storing munitions and military supplies, ports and railroads being used for the transportation of military supplies, and other places that are for the accommodation of troops or the support of military operations. Pursuant to the provisions of Article 25, HR, however, cities, towns, villages, dwellings, or buildings which may be classified as military objectives, but which are undefended (para 39b), are not permissible objects of attack.

*41. Unnecessary Killing and Devastation

Particularly in the circumstances referred to in the preceding paragraph, loss of life and damage to property incidental to attacks must not be excessive in relation to the concrete and direct military advantage expected to be gained. Those who plan or decide upon an attack, therefore, must take all reasonable steps to ensure not only that the objectives are identified as military objectives or defended places within the meaning of the preceding paragraph but also that these objectives may be attacked without probable losses in lives and damage to property disproportionate to the military advantage anticipated. Moreover, once a fort or defended locality has surrendered, only such further damage is permitted as is demanded by the exigencies of war, such as the removal of fortifications, demolition of military buildings, and destruction of military stores (HR, art. 23, par. (g); GC, art 53).

42. Aerial Bombardment

There is no prohibition of general application against bombardment from the air of combatant troops, defended places, or other legitimate military objectives.

43. Notice of Bombardment

a. Treaty Provision.

The officer in command of an attacking force must, before commencing a bombardment, except in cases of assault, do all in his power to warn the authorities. (HR, art. 26.)

b. Application of Rule. This rule is understood to refer only to bombardments of places where parts of the civil population remain.

c. When Warning is To Be Given. Even when belligerents are not subject to the above treaty, the commanders of United States ground forces will, when the situation permits, inform the enemy of their intention to bombard a place, so that the noncombatants, especially the women and children, may be removed before the bombardment commences.

44. Treatment of Inhabitants of Invested Area

a. General Population. The commander of the investing force has the right to forbid all communications and access between the besieged place and the outside. However, Article 17, GC (par. 256), requires that belligerents endeavor to conclude local agreements for the removal from besieged or encircled areas of wounded, sick, infirm, and aged persons, children and maternity cases, and for the passage of ministers of all religions, medical personnel and medical equipment on their way to such areas. Provision is also made in Article 23 of the same Convention (par. 262) for the passage of consignments of medical and hospital stores and objects necessary for the religious worship of civilians and of essential foodstuffs, clothing, and tonics intended for children under 15, expectant mothers, and maternity cases.

Subject to the foregoing exceptions, there is no rule of law which compels the commander of an investing force to permit noncombatants to leave a besieged locality. It is within the discretion of the besieging commander whether he will permit noncombatants to leave and under what conditions. Thus, if a commander of a besieged place expels the noncombatants in order to lessen the logistical burden he has to bear, it is lawful, though an extreme measure, to drive them back, so as to hasten the surrender. Persons who attempt to leave or enter a besieged place without obtaining the necessary permission are liable to be fired upon, sent back, or detained.

b. Diplomatic and Consular Personnel. Diplomatic and consular personnel of a neutral State should not be prevented from leaving a besieged place before hostilities commence, but this privilege cannot be claimed while hostilities are in progress. Should they voluntarily decide to remain, they must undergo the same risks as other inhabitants.

45. Buildings and Areas To Be Protected

a. Buildings To Be Spared.

In sieges and bombardments all necessary measures must be taken to spare, as far as possible, buildings dedicated to religion, art, science, or charitable purposes, historic monuments, hospitals, and places where the sick and wounded are collected, provided they are not being used at the time for military purposes.

It is the duty of the besieged to indicate the presence of such buildings or places by distinctive and visible signs, which shall be notified to the enemy beforehand. (HR, art. 27.) (See also GC, arts. 18 and 19; pars. 257 and 258 herein, dealing with the identification and protection of civilian hospitals.)

b. Areas To Be Protected. In order to protect buildings used for medical purposes from being accidentally hit, it is desirable that the wounded and sick should, if possible, be concentrated in an area remote from military objectives or in an area neutralized by arrangement with the enemy. See GC, arts. 14, 18, and 19; pars. 253, 257, and 258 herein, concerning the establishment of hospital and safety zones and localities.)

46. Such Buildings to Display Sign Specified in Naval Treaty

a. Treaty Provision.

It is the duty of the inhabitants to indicate such monuments, edifices, or places by visible signs, which shall consist of large stiff rectangular panels divided diagonally into two coloured triangular portions, the upper portion black, the lower portion white. (H. IX, art 5, 2d par.)

b. Application of Rule. The foregoing rule adopted in this convention for naval warfare may be adopted for protecting buildings under bombardment in land warfare.

c. Use of Foregoing for Military Purposes. The besieging forces are not required to observe the signs indicating inviolability of buildings that are known to be used for military purposes, such as quarters, warehouses, observation posts, or signal installations.

47. Pillage Forbidden

The pillage of a town or place, even when taken by assault, is prohibited. (HR, art. 28.)


48. Stratagems Permissible

Ruses of war and the employment of measures necessary for obtaining information about the enemy and the country are considered permissible. (HR, art. 24.)

49. Good Faith

Absolute good faith with the enemy must be observed as a rule of conduct; but this does not prevent measures such as using spies and secret agents, encouraging defection or insurrection among the enemy civilian population, corrupting enemy civilians or soldiers by bribes, or inducing the enemy's soldiers to desert, surrender, or rebel. In general, a belligerent may resort to those measures for mystifying or misleading the enemy against which the enemy ought to take measures to protect himself.

50. Treachery or Perfidy

Ruses of war are legitimate so long as they do not involve treachery or perfidy on the part of the belligerent resorting to them. They are, however, forbidden if they contravene any generally accepted rule.

The line of demarcation between legitimate ruses and forbidden acts of perfidy is sometimes indistinct, but the following examples indicate the correct principles. It would be an improper practice to secure an advantage of the enemy by deliberate lying or misleading conduct which involves a breach of faith, or when there is a moral obligation to speak the truth. For example, it is improper to feign surrender so as to secure an advantage over the opposing belligerent thereby. So similarly, to broadcast to the enemy that an armistice had been agreed upon when such is not the case would be treacherous. On the other hand, it is a perfectly proper ruse to summon a force to surrender on the ground that it is surrounded and thereby induce such surrender with a small force.

Treacherous or perfidious conduct in war is forbidden because it destroys the basis for a restoration of peace short of the complete annihilation of one belligerent by the other.

51. Legitimate Ruses

Among legitimate ruses may be counted surprises, ambushes, feigning attacks, retreats, or flights, simulating quiet and inactivity, use of small forces to simulate large units, transmitting false or misleading radio or telephone messages, deception of the enemy by bogus orders purporting to have been issued by the enemy commander, making use of the enemy's signals and passwords, pretending to communicate with troops or reinforcements which have no existence, deceptive supply movements, deliberate planting of false information use of spies and secret agents, moving landmarks, putting up dummy guns and vehicles or laying dummy mines, erection of dummy installations and airfields, removing unit identifications from uniforms, use of signal deceptive measures, and psychological warfare activities.

52. Improper Use of Identifying Devices

It is especially forbidden * * * to make improper use of a flag of truce, of the national flag, or of the military insignia and uniform of the enemy, as well as the distinctive badges of the Geneva Convention. (HR, art. 23, par. (f).)

53. Flags of Truce

Flags of truce must not be used surreptitiously to obtain military information or merely to obtain time to effect a retreat or secure reinforcements or to feign a surrender in order to surprise an enemy. An officer receiving them is not on this account absolved from the duty of exercising proper precautions with regard to them.

54. National Flags, Insignia, and Uniforms as a Ruse

In practice, it has been authorized to make use of national flags, insignia, and uniforms as a ruse. The foregoing rule (HR, art. 23, par. (f)) does not prohibit such employment, but does prohibit their improper use. It is certainly forbidden to employ them during combat, but their use at other times is not forbidden.

55. Improper Use of Distinctive Emblem of Geneva Convention

The use of the emblem of the Red Cross and other equivalent insignia must be limited to the indication or protection of medical units and establishments, the personnel and material protected by GWS and other similar conventions. The following are examples of the improper use of the emblem: Using a hospital or other building accorded such protection as an observation post or military office or depot; firing from a building or tent displaying the emblem of the Red Cross; using a hospital train or airplane to facilitate the escape of combatants; displaying the emblem on vehicles containing ammunition or other nonmedical stores; and in general using it for cloaking acts of hostility.


56. Devastation

The measure of permissible devastation is found in the strict necessities of war. Devastation as an end in itself or as a separate measure of war is not sanctioned by the law of war. There must be some reasonably close connection between the destruction of property and the overcoming of the enemy's army. Thus the rule requiring respect for private property is not violated through damage resulting from operations, movements, or combat activity of the army; that is, real estate may be used for marches, camp sites, construction of field fortifications, etc. Buildings may be destroyed for sanitary purposes or used for shelter for troops, the wounded and sick and vehicles and for reconnaissance, cover, and defense. Fences, woods, crops, buildings, etc., may be demolished, cut down, and removed to clear a field of fire, to clear the ground for landing fields, or to furnish building materials or fuel if imperatively needed for the army. (See GC, art. 53; par. 339b; herein, concerning the permissible extent of destruction in occupied areas.)

57. Protection of Artistic and Scientific Institutions and Historic Monuments

The United States and certain of the American Republics are parties to the so-called Roetich Pact, which accords a neutralized and protected status to historic monuments, museums, scientific, artistic, educational, and cultural institutions in the event of war between such States. (For its text, see 49 Stat. 3267; Treaty Series No. 899.)

58. Destruction and Seizure of Property

It is especially forbidden * * * to destroy or seize the enemy's property, unless such destruction or seizure be imperatively demanded by the necessities of war (HR, art. 23, par. (g).)

59. Booty of War

a. Public Property. All enemy public movable property captured or found on a battlefield becomes the property of the capturing State.

b. Private Property. Enemy private movable property, other than arms, military papers, horses, and the like captured or found on a battlefield, may be appropriated only to the extent that such taking is permissible in occupied areas (see pars. 405-411).

c.. Prisoners of War. The property which prisoners of war are to be allowed to retain is specified in Article 18, GPW (par. 94).

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