Electronic Warfare and the Law of Armed Conflict

by , | Oct 28, 2024

Earlier this year, we had the pleasure of participating in the “Future of Warfare and the Law Symposium” at U.S. Army Futures Command in Austin, Texas. The conference, which was co-sponsored by Army Futures Command, the Strauss Center for International Security and Law, and the Lieber Institute for Law and Warfare, consisted of a series of interdisciplinary discussions about how the law of armed conflict may address emerging technologies with potential military applications. The experts in attendance at the conference included scientists, international law experts from both academia and governmental practice, and experts in other fields such as philosophy and economics.

One of the topics discussed was the technological and legal aspects of electromagnetic warfare in future warfare. This post highlights and offers analysis of some of the operational and legal issues regarding electromagnetic warfare that were addressed. We begin by explaining relevant aspects of the electromagnetic spectrum and electromagnetic warfare. We then discuss two challenges that legal advisers will face in applying the law of armed conflict: first, when electromagnetic warfare constitutes an attack to which the law of targeting applies; and second, when electromagnetic warfare operations infringe upon the legal protection afforded to medical facilities. Certainly, the application of emerging military technology in the electromagnetic spectrum raises many legal issues besides the two highlighted in this post. Our hope is that this post serves as an example of the legal challenges associated with this technology and contributes to efforts to address those challenges.

The Electromagnetic Spectrum

Electronic warfare involves exploitation of the electromagnetic spectrum (EMS). The EMS spans a wide range of wavelengths which provides maneuver space consisting of all frequences of electromagnetic radiation including radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, x-rays, and gamma rays.

The EMS is described variably, and it is often difficult for those without technical expertise to understand it. For example, it has been referred to as a “collection of all electromagnetic radiation in the universe.” Somewhat more specifically, the EMS has been described as “the entire distribution of electromagnetic radiation according to frequency or wavelength.” Commonly, descriptions and explanations of the EMS focus on the significance of wavelength, which can be used to divide electromagnetic radiation into groups such as radio waves, microwaves, infrared radiation, ultraviolent radiation, x-rays, and so on.

Military doctrine extends explanation of the EMS beyond notions of waves and frequency. For example, U.S. Department of Defense (DoD) joint doctrine describes the EMS as a “maneuver space” in which the military operates to exercise “control within the operational environment.” Although it includes details about frequency bands and wave lengths, military doctrine further explains the kinds of equipment, groups, and various functions that perform specific tasks within the EMS. The latter includes, for example, civilian operations such as commercial aircraft and airports and cellular phone infrastructure.

It may be best to think of the EMS as a concept, that is, a construct the encompasses technical features such as frequency bandwidth, as well as the physical, human, and functional aspects of that technology. For example, military operators use a host of equipment including receivers, transmitters, and satellites to communicate within the EMS operating environment, thus enabling the “command and control” warfighting function in military operations.

Understanding the EMS as a concept facilitates the application of relevant law of armed conflict rules and principles. As we discuss below, law of armed conflict rules and principles are framed in terms of people and objects. For example, the principle of distinction inspires a set of rules that protect civilian persons and objects from direct attack. It thus seems that any complete analysis of the application of distinction to military operations in the EMS must appreciate the extent to which such operations impact people and objects in the physical world.

The EMS is a natural resource that private companies and government entities use for various purposes, such as remote sensing and communication. EMS is free to use by anyone without depletion or deterioration. But mismanagement, overuse, and misuse can cause interference among users. Although interference can sometimes be attributed to natural phenomena such as solar storms and other forms of space weather, intentional interference has become a serious problem since the 1990s and is now widely considered a measure of choice in modern warfare. As stated in Joint Publication 3-13.1 (Electronic Warfare), the use of EMS is essential to control the operational environment during all military operations.

Electromagnetic Warfare

Given the key role communications equipment and sensors play in military operations, it is unsurprising that electronic warfare is an important aspect of joint military operations. According to U.S. DoD joint doctrine, electronic warfare refers to “military actions involving the use of electromagnetic and directed energy to control the EMS or to attack the enemy” (U.S. military doctrine uses the term “electromagnetic warfare”). The U.S. Army uses electronic warfare to “gain and maintain positions of relative advantage within the EMS.” The Army contributes to electronic warfare operations through three divisions: electromagnetic attack, electromagnetic protection, and electromagnetic support.

States often use electronic warfare to interfere with adversary sensing, communication, and navigation capabilities. The capability to intentionally interfere with the EMS includes jamming that disrupts radio communication or positioning, navigation, and timing signals. Typically, jamming involves emitting high power signals across a wide spectrum of radio frequency (out-of-band jamming) to cause disruption to communication and navigation signals that use neighboring slots within the reach of these signals. Alternatively, jamming can cause a service channel disruption by injecting a signal within the target channel bandwidth within the transmission window (in-band jamming) to prevent detection.

On the other hand, spoofing involves broadcasting false signals to deceive receivers. Applied to global navigation satellite signals such as GPS, spoofing can cause receivers to compute incorrect positioning, navigation, and timing data to misdirect GPS-guided systems to a different location. These electronic warfare capabilities find useful applications in wartime to disrupt, deceive, deny, or degrade the adversary’s communications, navigation, and command and control.

Russia is known to integrate electronic warfare in all branches of its military. Russia has embedded electronic warfare capabilities across its army, navy, and air force at the strategic, operational, and tactical levels. Russia’s use of electronic warfare in its aggression against Ukraine has reportedly caused widespread disruption of GPS signals in the Baltic region, disrupting navigation of hundreds of civilian aircraft.

Electronic warfare has the potential for further development as counter-drone capabilities by jamming and disrupting the communication and navigation system of uncrewed vehicles. The People’s Republic of China has been experimenting with a sophisticated new electronic warfare system that is capable of spoofing GPS signals used for automatic identification system transponders against ships navigating around the port of Shanghai. Earlier in the year, speculation went viral when the chair of the U.S. House Intelligence Committee raised alarm about a new Russian nuclear anti-satellite capability that might have involved the use of electromagnetic pulse energy with a flood of highly charged particles to disable earth-orbiting satellites.

Various counter-electronic warfare capabilities have emerged to address these threats. Technical countermeasures such as frequency-hopping and adaptive polarization go some way to alleviate the effects of jamming. Australian-made “cardboard” drones debuted in the Russia-Ukraine conflict and prevailed over Russian electronic warfare capabilities. Inertial navigation systems can substitute GPS navigation by guiding missiles and vehicles when satellite signals are unreliable or sabotaged.

Modern electronic warfare capabilities have also developed into sophisticated forms capable of causing direct harm to the adversary. With the production of electromagnetic energy in a concentrated form or atomic/sub-atomic particles, directed energy weapons such as high-power microwave or high-power radio frequency systems can cause tissue damage in the human body and induce neurological and neuropathological changes in the brain. High-energy lasers, with a sufficient level of irradiation, can incapacitate, damage, or destroy enemy personnel and assets.

Attacks

As with all military operations, the use of electronic warfare capabilities during an armed conflict must comply with the law of armed conflict. The applicable legal rules for electronic warfare depend in part on whether the particular use of electronic warfare amounts to an “attack.” This question is relevant because attacks are a subset of military operations that are governed by a robust set of legal rules during an armed conflict.

Before addressing the definition of and legal rules governing attacks, it is important to distinguish the term “attack” under the law of armed conflict from the same term used in electronic warfare military doctrine. The latter broadly encompasses electronic warfare operations involving the use of electromagnetic energy, directed energy, or antiradiation weapons including sensor jammers that disrupt the flow of information between or among the enemy’s military communication systems. This difference in terminology requires lawyers and military operators to be clear in explaining and analyzing legal issues involving EMS technology and capabilities. 

The law of targeting, as codified in Part IV of Additional Protocol I to the Geneva Conventions and, in most parts, reflective of customary international law, applies to military operations that constitute attacks. An attack is an act of violence against the adversary, whether in offense or defense. When an EMS operation qualifies as an attack, it must be directed at legitimate military targets and the incidental harm it is expected to inflict upon civilians and civilian objects must not be out of proportion to the anticipated military advantage. Thus, whether an EMS operation amounts to an attack is a critical threshold question that must be answered before assessing its legality.

Weapon systems that cause physical harm and damage typically raise no critical legal questions about the attack threshold. However, this question can be challenging for weapons that have non-kinetic effects, including electronic warfare capabilities. Many jurists would agree that the use of EMS can be deemed an attack when it is reasonably expected to cause an injurious or damaging effect (Tallinn Manual 2.0, rule 92; Boothby, p. 384). For example, the use of high-energy lasers that are designed to destroy enemy assets such as drones and missiles would constitute an attack and their use is therefore subject to targeting rules, including for example the prohibition on attacks directed against civilians and civilian objects and the prohibition against indiscriminate attacks.

The attack assessment becomes more difficult when an electronic warfare capability is designed to cause temporary, non-kinetic effects, but creates risks of potential physical damage. Consider, for example, high-energy lasers designed to blind satellite sensors, the use of which risks causing physical damage to optical sensors due to unmeasurable factors such as the strength of the sensor films or the fluctuation of environmental conditions through which laser beams are to travel. Whether use of such electronic warfare capabilities constitutes an attack could depend on legal notions such as “reasonable foreseeability,” as well as difficult factual assessments.

Jamming is the use of electronic warfare capabilities to disrupt, usually temporarily, the signals relayed through the EMS between communication equipment and sensors. In general, jamming is not considered as an attack because of its temporary and non-destructive effects. As such, jamming is not subject to law of armed conflict targeting rules. Jamming is therefore less regulated under the law of armed conflict and may under some circumstances be used, for example, against civilian EMS equipment and infrastructure. However, operators must potentially consider other legal requirements, such as the duty of constant care to spare civilians from the effects of military operations. The precise bounds of this requirement are debatable.

Some uses of jamming may cross the attack threshold. This is certainly the case when its use is intended to cause death, injury, or destruction. For example, jamming would qualify as an (unlawful) attack in cases where it is intended to cause collision of aircraft or prevent rescue missions from reaching a particular area hit by an earthquake knowing that deaths will increase as a result. Less clear and more debatable are cases in which the risk of collision or potential disruption to rescue efforts is merely foreseeable but is not an intended target at which the operation is directed.

Further challenges arise when those employing electronic warfare anticipate behavior adjustment by those who might be affected. A belligerent party may employ barrage jamming over an extended area in international airspace and on the high seas, anticipating that modern civilian aircraft and ships are fitted with an advanced inertia navigation system. A directed energy weapon may be employed against a residential area with an anticipation that the acute short-term pain it generates is sufficient to cause people to move out of the area before inflicting physical injury. Views might be divided as to whether acting on the basis of such anticipation may fall afoul of the distinction rule.

Protection of Hospitals

Under Article 19 of the First Geneva Convention of 1949, medical establishments and units are specifically designated as essential elements of the medical service that “shall at all times be respected and protected.” Belligerent parties are not only prohibited from making hospitals and mobile medical units an object of attack but also from interfering with their work.

The U.S. DoD Law of War Manual interprets this obligation such that medical units and facilities must not knowingly be attacked, fired upon, or unnecessarily prevented from discharging their proper functions (§ 7.8.2). Therefore, questions arise whether the use of electronic warfare, for example, to disrupt communications, can be construed as interfering with medical services or unnecessarily preventing their proper functions even if it does not amount to an attack as discussed above.

In a recent updated commentary, the International Committee of the Red Cross has expressed the view that this obligation to respect extends to the prohibition of an intentional disruption of the medical facility’s ability to communicate for medical purposes (para. 1804). This interpretation would suggest that an electronic warfare operation designed to jam enemy communication would violate the obligation to respect under Article 19 of the First Geneva Convention if it was expected to cause, at the same time, a hospital in the conflict zone to experience a communication “black out.”

However, there are problems with such an interpretation in that technically, communications used for medical services are indistinguishable from other communications that are taking place in the conflict zone. In the physical world, hospitals are well recognizable by their buildings, vehicles, personnel, and associated symbols. However, hospitals do not emit a special kind of electromagnetic wave and they do not necessarily transmit on a special frequency, which would allow military operations immediately to identify them as hospitals. The point is not to claim that distinction is impossible in the EMS, or that military operators could never identify hospitals based on EMS activity. Rather, the point is to caution against an over-reliance on and simplification of EMS activity through legal interpretation. Instead, lawyers and operators must take care to understand the capabilities and limitations of EMS technology, so that legal reasoning can be based on sound underlying logic.

Concluding Thoughts

Technology is rapidly advancing to enable military forces to exploit the EMS in ways that could not have been possible in the wars of the past. Electronic warfare is no longer conceived only as a means to disrupt, deceive, deny, or degrade the adversary’s communications, navigation, and command and control but has the potential to become a weapon of choice against drones and to cause more direct harm to the adversary. However, the application of existing rules to new electronic capabilities is not straightforward. Unmeasurable environmental factors and the anticipation of behavior adjustments complicates legal assessments.

Efforts will be made to overcome these challenges by drawing an analogy to existing capabilities and military practices. Indeed, analogical reasoning in legal analysis is common. No two cases are identical, yet lawyers and others often reason by spotting relevant similarities between cases. Such reasoning often takes on wholesale proportions. For example, the Tallinn Manuals are well-known examples of analogical reasoning, insofar as each sought to apply international law principles and rules designed for military operations in traditional warfighting domains to operations conducted in cyberspace.

However, lax analogical reasoning based on the policy of convenience runs the risk of impractical interpretation, uninformed of technological capabilities and limits. Such an approach carries risk and, in certain cases, could lead to impractical interpretations, uninformed of technological capabilities and limitations. Developing familiarity with the subject matter before conducting legal analysis is of the essence and a form of due diligence expected of legal practitioners, scholars, and other professions.

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Robert Lawless is an Assistant Professor in the Department of Law and Managing Director of the Lieber Institute for Law & Land Warfare at the United States Military Academy, West Point.

Hitoshi Nasu is a Professor of Law in the Department of Law at the United States Military Academy.

 

 

 

 

 

Photo credit: U.S. Air Force, D.P. Heard

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