Weapons and the Law of Warfare

Weapons and the Law of Warfare

. 12 min read

M.J. Peterson. Originally published in the HIR March 1980 Issue.

A decade ago, international concern about belligerent weapons choices focused mainly on American weapons used in Vietnam and resulted in attempts to establish some new and clearer rules on weapons choices and uses. Today, concern focuses on Soviet uses of napalm in Afghanistan and Soviet and Vietnamese use of poison in Afghanistan, Laos, and Cambodia, familiar weapons being used in familiar ways.

Belligerents are al- ways tempted to use everything they have that seems necessary for winning the war at hand. However, current technology and industrial techniques give them large stocks of extraordinarily destructive weapons, making the limitation of weapons choices an important concern. The international community has tried to limit belligerent weapons choices through its legal system, but its success has not been great. To understand why, one must understand how (international law is made and enforced in general, and then how it works in particular cases.

Making a rule limiting the choice of weapons is not easy, partly because of the
nature of the international political system and partly because, given that system, states are loath to yield much discretion.

The international system lacks a central legislature that makes rules that bind all individual members of the international community. Instead, the states agree on rules in negotiations among themselves. Though intergovernmental organizations like the United Nations assist in this process, no rule becomes part of positive international law without the express or tacit consent of states.

Although any law-making body considers the effect of proposed rules on the interests of individual members of society, individual interests receive more consideration in the making of international law for two reasons. First, there are fewer members, and all participate in law-making. Thus, they can consider their own and others' interests in detail. Second, the process of international lawmaking resembles the making of contracts more than the passing of legislation in domestic society. Individual members make many special rules in negotiations with one or a few others, and can even opt out of general rules by refusing to sign the relevant treaty or by signing the treaty with various "reservations" or "understandings" limiting their acceptance of certain rules.

This process of rule-making occurs in a political system that also lacks central agencies to interpret rules, enforce rules, protect individuals from violence, and adjust rules to social change. In the international system all of these are accomplished by self-help, the most potent form of which is war. States take this into account in rulemaking, and build it into international law in many ways.

The law of war thus begins with the assumption that war will continue to play an important role in international politics. It then attempts to establish rules for the resort to war that will decrease its use, and, more pertinent to the present discussion, rules for the conduct of war that will limit its destructiveness. These latter rules, often called the law of warfare, seek to balance the pursuit of the legitimate goal of war against three limiting considerations.

Most simply put, states at war seek to reduce or destroy their enemy's ability and/or will to resist so that they may impose their will on that enemy. Left unchecked by other considerations, this basic and legitimate goal of war can lead to vast destruction, particularly when a state decides that it must destroy the enemy's ability and will to resist. Most of the time, however, all states agree that war is not worthwhile if the result is a depopulated wasteland. To prevent this, three legal principles are used to limit the amount of allowable destruction: humanity, chivalry, and proportionality.

Humanity denotes the belief that combatants and civilians alike should be exposed to no more danger than is necessary to achieving the legitimate goal of warfare. It affirms the belief that weakening enemy resistance requires only that combatants be put out of action temporarily and allows civilians to be spared as much as possible. Today, these older notions of humanity are being supplemented by ideas on human rights, which express belief in the dignity and intrinsic worth of the individual and limit all government abuses of person in peace as well as war. However defined, the principle of humanity suggests definite limits to belligerent conduct, and has direct relevance to the choice of weapons. In particular, it suggests that weapons causing "unnecessary suffering" or (from the more precise French) "superfluous injury" be banned.

Chivalry denotes standards of fairness and mutual respect that are expected to prevail even among enemies. Today's notions of chivalry are not as elaborate or as socially restricted as medieval European ideals of the perfect knight; but the principle does persist in rules prohibiting such practices as false use of medical signs to  hide able-bodied combatants or feigning surrender while actually preparing to attack. Though used in the past to support bans on certain weapons, like the cross-bow, as "ungentlemanly," the principle of chivalry has little direct relevance to weapons today.

Proportionality means that damage inflicted should not grossly exceed gains won or legitimate values at stake and that action taken should not grossly exceed that necessary for attaining or defending legitimate goals or values. This principle is quite familiar in other branches of the law of war, particularly in doctrines of self-defense and reprisal (which also has peacetime uses). There have always been a few aberrant cases in which states sought complete destruction or momentarily abandoned all restraint. Yet notions of avoiding excessive costs do pervade warfare–if only in the self-interested form of avoiding too much loss to oneself. Judgements of what is proportional will differ, but there is nearly always a point beyond which all agree that destruction becomes disproportionate. Development of Nuclear bombs, weather modification techniques, toxins, and defoliants obviously made proportionality relevant to weapons evaluation.

Making Rules on Weapons

The balancing of the legitimate goal of war with the three limiting principles provides the framework in which experts debate and governments decide whether to permit or prohibit specific weapons. Because governments are generally slow to forego any weapon they have developed, bans tend to cover weapons that do not provide much military advantage over similar, less destructive weapons (e.g. "dum-dum" bullets), that can be as dangerous to the user as to the target (e.g. toxins), or that offer advantages that can be more than cancelled by the enemy's adoption of the same weapon (e.g. poison gas).

Deciding which weapons to ban is not easy. States – and even reasonably well-equipped guerrilla and terrorist groups – can choose today from a vast array of weapons ranging from rocks to nuclear devices. All weapons kill or injure people and animals and damage or destroy plants and things; the main difference among them lies in how quickly they do how much. It is possible to kill every person and animal in a country and destroy its farms, towns, and industries with rocks and sticks; however, the impatient are likely to prefer using nuclear bombs and chemicals. If all possible weapons could be arranged on a continuum according to type and relative destructiveness, it would be possible to locate a point on the continuum separating the prohibited from the permitted. Unfortunately, this cannot be done.

First, many weapons are not directly comparable because of differences in intended use. Just how does one compare a rifle or a machine gun to an anti-aircraft missile or a destroyer? At the very least, one would need to set up several continua, but this presents the formidable problem of keeping the dividing point on all of them related in some meaningful way.

Second, and more seriously, experts and governments differ in their evaluations of weapons. For whatever reason, some experts and governments are willing to accept the use of weapons that others find too destructive. For example, the Swedish government has campaigned for more than a decade to have napalm banned, but most other governments believe that its military usefulness against certain targets outweighs the problems arising from its hitting unprotected flesh (see Conference of Government Experts on the Use of Certain Conventional Weapons [1974-76]). The particular problems of guerrilla war lead governments to different weapons choices than they would make in wars between conventional standing armies.

Individual governments can decide to forego a weapon, but no general legal ban will occur until all agree. Because international law follows the maxim "what is not prohibited is permitted," bans are few. To date, weapons have been considered individually, though now there is a l proposed rule that would ban any yet-to-be-developed weapon that violated general international legal standards on destructiveness (see Protocol I to the 1949 Geneva Conventions, Articles 35-36). Given the difficulties of reaching agreement, the current list of banned weapons looks quite arbitrary. It includes:

(a) barbed lances,
(b) projectiles filled with glass,
(c) chain or bar shot,
(d) red-hot cannon balls,
(e) explosive or incendiary projectiles weighing less than 14 ounces,
(f) "dum-dum" bullets (bullets with soft cores or scored surfaces that expand after entering the body),
(g) irregularly shaped bullets,
(h) poisonous and poison-covered weapons,
(i) asphyxiating or poison gasses,
(j) chemicals harmful to man,
(k) toxins and disease-producing microbial and bacteriological agents, and
(l) (proposed) environmental modification techniques.
(Text of the relevant treaties can be found in Leon Friedman, International Legal Materials Vol. 1 11:309 (1971) and Vol.2 16:88 (1977).)

Many might ask why nuclear weapons are not on the list. They are destructive; however, they also confer many military advantages, including (so far) increased ability to avoid general war. Nuclear deterrence is a scary way to avoid World War III, but nothing else the twentieth century has tried has worked as well.

Enforcing the Rules

Banning a weapon does not assure its absence on the battlefield; states must also comply with the ban when they go to war. In the international system, as in any social system, individuals obey the law for one or more of three reasons:
(a) conscience: belief that a particular law is morally justified or at least morally unobjectionable, and or belief that because it contributes to social stability, obedience to law is good in itself;
(b) calculation: decision that obeying the law will bring material benefit in the general form of a reputation for dependability and virtue or in some specific form; and
(c) coercion: fear or experience of externally applied positive or negative sanctions.

In no social system is there complete compliance with every law, but the international system has several features which often discourage obedience. These are seen most readily by contrasting the international system with stable domestic systems.

In a stable domestic society, individual conscience is supported by a broad ethical consensus among the members of that society and by institutions that help assure individual survival. Though members may disagree about particular ethical questions, they do accept some common identification and some common restraints on the conduct of ethical controversies. The central institutions can, if necessary, impose restraint. Both consensus and central institutions are absent from the international system. Members are likely to disagree strongly about ethical conceptions, and when they do the most likely result is sharp ideological competition often resulting in war. Though there have been periods of ethical consensus in the international system, the current era is marked by a lack of consensus and the simultaneous existence of several ethical visions with global ambitions.

In a stable domestic society, the ethical consensus and central institutions help individuals restrain their pursuit of individual interest and build expectations of cooperation. The central institutions assure protection of common interests (even if in ways that favor some individuals over others). Ethics and institutions limit the methods of seeking material interests and help individuals take a longer-term view than they might on their own. Thus, abuse of greater strength does not often result in the destruction or loss of independence of the weaker. In the international system, notions of common interest are limited to avoiding general destruction (despite the best efforts of those promoting ideals of global cooperation), and neither ethics nor institutions assure their protection or limit the pursuit of individual interest. Abuses of strength are normal, and often result in the destruction or loss of independence of the weaker.

Stable domestic societies have vertical legal systems. The central institutions can command every member of society, have a legal monopoly on the legitimate use of force, and have the practical predominance of power them to overawe any individual (though not all individuals all at once). Individuals may thus look to society's central institutions for maintenance of order and protection. The international legal system is horizontal.
Law is made by negotiation; there is no legal monopoly of the legitimate use of force (the U.N. Charter as written creates one, but as practiced does not) and no institution with the predominance of power needed to bring any
individual state to account. This means that individual states must look to reciprocity of interests, self-help, and coalition with others to maintain order and protect themselves from attack. It is true that domestic law often depends on reciprocity, but the central institutions can be engaged when it breaks down. In the international legal system, reciprocity is backed only by self-help and coalition.

Unbuttressed by ethical consensus and effective central institutions, conscience, calculation, and coercion seldom form a mutually reinforcing set of restraints in world politics. Often they cancel one another. Nowhere is this more apparent than in the law of war.

When inclined toward restraint, conscience provides a good, but not completely reliable, support for law. States wishing to obey the law of war for ethical reasons will, at least as long as their enemies do. Once the enemy violates a rule, even the most self-restrained state may have to respond in kind, either to deter further violation or to avoid losing the war. However, many states apply few ethical restraints to war. The stress of the situation, the importance of the goals, and the maxims of survival- oriented statesmanship all encourage the sort of ethics in which the end (victory) justifies all means.

Calculation can reinforce a wavering conscience, but cannot often substitute for one. If anything, wartime calculation is likely to erode conscience because war favors a relative lack of restraint Winning is better than losing, and winners can usually live down any opprobrium they garner from violating the law of war. Those statesmen who consider a reputation for toughness and irrationality an advantage in international politics often find war the best place to cultivate it. The only sort of calculation likely to impose restraint is that which seeks to avoid risking too much or arousing more resistance than already exists.

Coercion can support law where conscience and calculation waiver or favor lack of restraint, but its availability is quite uncertain. If an enemy cannot respond in kind or in another equally damaging way reciprocity will not uphold law. Sanctions imposed by third states acting individually or through intergovernmental organizations will not be available most of the time. Lack of concern, fear of belligerent response, or sympathy with the violator may induce individual states to ignore the situation, particularly because there are few norms encouraging concern on the part of third states. Intergovernmental organizations may not be able to mount effective collective action because of institutional constraints (e.g. Security Council vetos), member disinclination, or dilution through individual noncooperation. Only rarely do states lose wars so completely that those responsible for violations of the law of war can be brought to some form of international justice, and the state made to bear some penalty, such as reparations or loss of territory.

Considering Particular Cases

Considering the cases of specific belligerents, here the Soviet Union and Vietnam, will clarify this rather abstract discussion. Two questions must be answered in order to understand the legal significance of their actions. First, have they violated international law? Second, if they have, what can be done about it?

Unfortunately, there have been no violations of international law in Soviet use of napalm and Soviet and Vietnamese uses of poison gas. Napalm has not been banned by any international agreement now in force. Even the widespread belief that it should not be used against unprotected combatants has not been institutionalized as a rule of law yet. There are treaties banning the use of poison gas, but they affect only those states signing them, and then only within the terms of any reservations they attach. (There are a few occasions on which multilateral treaties expressing general rules can become binding on all states, but they do not apply to the bans on poison gas.

Thus Vietnam, which is not a party to these treaties, violates no international rule by using mustard gas. The Soviet Union is a party to the 1925 treaty, but with the common reservation that it will be bound to observe the ban only in wars with other parties to the treaty, and then only as long as the other state and its allies abide by the ban (see text of the Soviet reservation in League of Nations Treaty Series, 94:71 [1929]). Afghanistan is not a party to the ban (U.S., Department of State, Treaties in Force, 1979, p.278), so the Soviets are not bound by it in a war. The Soviets insist that they are not at war with Afghanistan; they claim they are helping the legitimate government put down rebellion. This still permits them to use gas, however, because none of the treaties banning it apply to civil wars.

Even if the Soviets and Vietnamese were bound by rules banning napalm and poison gas, their violations would probably exist and go unpunished. Conscience probably encourages violation because they see themselves as locked in a struggle to help "progressive forces" prevail over unscrupulous "reactionary" ones. Calculation clearly inclines them toward use of napalm and poison gas. Both seek to break guerrilla resistance as quickly as possible and must drive their enemies out of remote and inaccessible areas to do this. Napalm and poison gas have proven to be among the most efficient means to this end. Coercion did not and will not stop them because it is not available. Both can safely assume that the guerrillas lack the capability to retaliate in kind or in any other equivalent way.

Thus maintenance of reciprocity by enemy self-help is impossible. Third state and international sanctions are also unavailable. Most third states cannot respond in any meaningful way, and some do not care to. Others can respond, but are hampered by lack of clear rules specifying when and how they can respond and by greater concern with wider issues such as the legality of the invasions or the future intentions of the invaders. The actions being taken by third states, such as condemnations at the U.N., Olympic boycotts, and grain embargoes, respond to the wider concerns. Collective sanctions through the U.N. are unlikely because the Soviets can veto any Security Council initiative and because the General Assembly is also more concerned about the wider questions.

Thus the international community is again unable to prevent or punish the use of particularly terrible weapons in war through its legal institutions. This does not destroy those legal institutions, but does show their weakness. This weakness is inherent in any legal system that is horizontal and serves a social system marked by little ethical consensus. Only when consensus increases to the point that states forego war as a method of self-help or when effective central institutions impose a vertical legal a system on states will this weakness