Legal and policy constraints on the conduct of aerial precision warfare.

Author:Canestaro, Nathan A.


Focusing his historical analysis on World War II, Mr. Canestaro describes how the substantial legal and policy controls under which the U.S. military conducts its air campaigns meet or exceed the requirements of international treaties and the customary practice of states. Bombing technology has only recently developed to the point of allowing compliance with international legal standards, and the United States has implemented stringent measures in recent conflicts to minimize unintended civilian casualties in warfare. Mr. Canestaro demonstrates that because these self-imposed restrictions go beyond the point of mere compliance, they often constitute a disadvantage to the conduct of U.S. military operations. Strict U.S. military compliance with international legal standards and self-imposed policy restrictions derived from political fear of excessive casualties insure that adversaries are rarely engaged with the full measure of U.S. military might.

The development of precision weapons over the last several decades has made armed conflict both more and less lethal. Against his established historical background, Mr. Canestaro measures modern U.S. military practice and technology against the customary standards, concluding that self-imposed legal and policy restraints designed to protect civilian lives have risen in step with technological developments allowing greater precision and thus avoidance of collateral damage. This situation continues significantly to shape the conduct of campaigns and to offer advantages to U.S. adversaries who choose not to follow the customary standards as faithfully.

TABLE OF CONTENTS I. INTRODUCTION II. THE EVOLUTION OF LAW AND TECHNOLOGY RELATING TO PRECISION BOMBING A. Pre-World War I B. World War I and the Interwar Period C. World War II's "Crisis of Distinction" D. Vietnam and Protocol I E. The Gulf War and Beyond: Precision Warfare Comes of Age III. THE RULES OF WARFARE A. Military Necessity B. Discrimination (Distinction) C. Proportionality D. Humanity (Unnecessary Suffering) IV. THE RULES OF ENGAGEMENT A. What Are RoE? B. How Are RoE Implemented? C. How Does Policy Affect RoE? V. WHERE THE RUBBER MEETS THE ROAD: POLICY AND LAW DRIVING MILITARY OPERATIONS A. Limitation on Choice of Targets and Method of Attack B. Sensitivities to Friendly Casualties or Collateral Damage VI. THE COSTS OF PLAYING FAIR VII. CONCLUSION I. INTRODUCTION

"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." (1) Lieber Code, 1863. "In war the main idea is to get the bombs on the targets." (2) General Curtis LeMay, U.S. Air Force, 1995. In the last few years, the media has devoted much time and effort to documenting the civilian deaths that have resulted from U.S. military operations around the globe. Every death is a tragedy, but in Kosovo, Afghanistan, and Iraq, the press has sensationalized these deaths rather than determining whether they could have been prevented. Although the media has publicized the impressive capabilities of precision weaponry, it has not conveyed that military campaigns are not precise merely because the weapons are. Contrary to Cicero's adage, silent enim leges inter arma, (3) the U.S. military operates under strict limitations imposed by civilian political administrations and the requirements of the law of war. It is the combined effect of these "rules of engagement" and the capabilities of precision weaponry that have reduced civilian casualties in recent conflicts.

These restrictions on U.S. military action are driven as much by political fear of public reaction to casualties as they are by respect for the law, and are often stricter than the law of war would otherwise require. Regardless of the motives, the U.S. commitment to the prevention of noncombatant deaths is extraordinary when viewed in the context of the difficulty of distinguishing military targets from nearby civilian areas, the technical challenges to precise aerial bombing, and the conduct of many U.S. opponents, who often attempt to exploit U.S. adherence to the law to their advantage.

This Article will establish that the U.S. military conducts its air campaigns under substantial legal and policy controls that meet or exceed the requirements of international treaties and the customary practice of states. Furthermore, this Article will demonstrate that these self-imposed restrictions go beyond the point of mere compliance and can be so strict as to constitute a definite disadvantage against adversaries who attempt to leverage U.S. compliance for their own military gain. In spite of these apparent drawbacks, the United States maintains a system of exhaustive legal review in a target acquisition cycle where speed is often critical and respects arbitrary policy restrictions that may never allow the enemy to be fully engaged by the full measure of U.S. military might.

In order to establish this claim, this Article will first examine the development of the legal standards that apply to aerial bombardment and the related technology and tactics. This will serve to illustrate that until the end of the Vietnam war, the technology of aerial bombardment was, to a large degree, not capable of achieving the precision required by the accepted law. By comparing the customary practice of nations with the standards codified in international treaties, this Article will establish that "the history of bombardment regulation shows a distinct utilitarian development, in which the idea of military effectiveness dominates, and in which the doctrines of permissible violence and social sanction are of secondary importance as checks or influences." (4)

This Article will focus its historical analysis primarily on World War II as evidence of customary practice, because the crucial national interests at risk in that conflict forced all parties to cede no advantage and comply only with the most basic standards for wartime conduct. (5) Brief examinations will also be made of the use of air power in regional conflicts that followed the development of precision weapons, such as the Gulf Wars, Kosovo, Afghanistan, and, to a lesser degree, Vietnam. These will serve to contrast modern U.S. practice and technology against the customary standard and to determine the degree to which legal and policy restraints actually shaped the conduct of those campaigns.


    The basic legal restrictions on the conduct of aerial bombing are based on the international laws of armed combat, sometimes referred to as the "law of war". It is "that part of international law that regulates the conduct of armed hostilities." (6) This body of law is derived from both codified law, such as treaties and conventions, and the customary practices of warring states. (7) It "restricts both the means of waging war and the objects against which such means may be employed." (8)

    The law of war has two specific shortcomings in regard to the conduct of air operations. First, little of it is specifically dedicated to aerial warfare. Those few treaties and conventions dedicated to air combat, or containing provisions that mention it specifically, are either unratified or have not been recognized as binding by the United States. Thus, legal practitioners have been forced to adapt to the subject of air operations the body of law that covers land or naval warfare or the use of force generally, (9) much of which was drafted before the development of powered flight.

    A second shortcoming in the conduct of air operations is that the law of war is not enforceable upon nations in the traditional sense; no permanent international judicial body with the necessary universal jurisdiction exists to enforce it, and domestic courts only rarely adjudicate violations. (10) Instead, compliance with the law often stems from decisions of national policy or military necessity--suggesting that in the most serious conflicts, limitations on warfare are more likely to be abandoned entirely. (11) In this manner, the laws of war are "respected and enforced [between opposing states] in an ongoing process of reciprocation and retaliation. Arrangements that seemed to be in the common interest of the antagonists [are] respected so long as compliance [is] reciprocal." (12)

    1. Pre-World War I

      Although much of the law of war has been derived from the practice of nations and the Christian "just war" tradition, it was not until the industrialized wars of the late nineteenth and early twentieth centuries that the law of war began to be formally codified. The "written and organizational genesis" (13) of this modern body of law was the 1863 Lieber Code. Drafted by Columbia University Professor Francis Lieber and implemented as the U.S. Army's General Orders No. 100, this code was the first attempt to draft formal regulations based on customary practice. (14) It reflected the traditional permissibility of attacks on all enemy combatants, stating that "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." (15) Under the justification of military necessity, the Lieber Code also allowed attacks against other targets that "are indispensable for securing the ends of the war, and which are lawful according to the modern law and usages of war." (16) It also recognized the traditional immunity of noncombatants, but conceded that they could not be completely separated from the burdens of the conflict:

      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 war.... Nevertheless, as civilization has advanced ... so has ... the distinction between the private individual belonging to a hostile country and the hostile country...

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