Intelligence Wars, Their Warriors, and Legal Ambiguity – Part II: Ambiguity
Editors’ note: This post is the second in a two-part series that explores the role both military and civilian intelligence organizations perform in armed conflict.
The first post in this series examined intelligence-based activities related to large scale combat operations (LSCO). It identified some of the intelligence-led, specialized military and paramilitary forces involved, and discussed the use of “undercover” operations. This second post identifies several factors that highlight the ambiguous nature of the law governing the use of these forces, which facilitates and masks a wide range of clandestine and covert operations.
Legal Ambiguity and Shadow Conflict
In LSCOs, it is questionable whether the law applicable to armed conflict is sufficiently comprehensive or settled to establish “where the law of war begins and ends and where policy, legitimate and prudent, begins and ends” (p. 7). Such conflicts unfold in a complex legal environment that is strategically permissive and about which experts express conflicting interpretations of the law. It is an environment where the use of “behind the lines” military and paramilitary units acting undercover is lawful, subject mainly to narrow restrictions arising from perfidious criminal acts. It is furthermore an environment where ambiguity facilitates and masks a wide range of clandestine and covert operations.
Several factors impact the efficacy of the legal frameworks applicable to warfare. These include: a continuing embrace of nineteenth-century criteria for combatant status; the longstanding connection between unprivileged belligerency and espionage; a narrow definition for war crimes involving perfidy; and a requirement for occupying powers to govern territory, which inevitably involves policing. There is also a startling lack of consensus among legal scholars concerning the exercise of State self-defence and how that legal framework relates to the commencement and termination of armed conflict. Ultimately, fertile ground exists for operations to unfold in the shadows.
Regarding combatant status, the basic criteria for lawful belligerency and prisoner-of-war (POW) status still rely mainly on visual criteria firmly rooted in nineteenth-century warfare including: the wearing of uniforms; adopting fixed, distinctive signs recognizable at a distance; and the open carrying of arms (1907 Hague Land Warfare Regulations, hereinafter, “Hague Regulations”), art. 1). This is so, even though there is no consensus about those criteria. By the early 20th century, State armed forces were starting to camouflage themselves due to engagement with irregular forces outside of Europe that did not fight openly. Furthermore, advances in weaponry made open warfare exceptionally lethal on the conventional battlefield. These trends intensified over the next century.
A bias towards conventional open warfare continued after the Second World War even though the Allies directly supported and participated in intelligence gathering, sabotage, and direct action in Axis-occupied countries. Article 4A of the 1949 Third Geneva Convention maintained what are widely viewed as unrealistic visual combatant status criteria for resistance organizations. Similarly, Article 44 of the 1977 Additional Protocol I (AP I) gave greater recognition to armed groups operating in civilian clothes and the State special forces supporting them.
However, the United States rejected AP I as endangering “civilians among whom terrorists and other irregulars attempt to conceal themselves.” This was and remains a problematic position, given the United States’ continuing involvement in irregular warfare and its widescale employment of special operations forces in support of armed groups. Such reluctance by the United States and others to adopt AP I has left the issue of combatant status in a state of uncertainty.
State Practice
Significantly, a link exists between States’ employment of specialized units and espionage. The international law governing espionage can best be described as unsettled but ultimately permissive. During peacetime, there are two perspectives, with the most extreme elements of the restrictive “formalist” camp suggesting foreign intelligence gathering is contrary to both international and local law. In contrast, the “realpolitik” approach acknowledges few limits on such activity. One dominant theory is that widespread State involvement in intelligence gathering means it is either not regulated by international law or is affirmatively permitted.Ultimately, it is policed by the prosecution of captured spies under domestic law.
Regarding wartime intelligence gathering, the 1942 Quirin Case (p. 31) wrongly conflated spies with unlawful combatants suggesting spies were “offenders against the law of war.” Rather it is widely accepted that “[b]y the law of war it is lawful to use spies” (Hostage Case, p. 1245). Espionage during international armed conflict is authorized by both treaty (Hague Regulations, art. 24) and customary international law (see here). Thus spying is authorized during international armed conflict, even though it involves deception, deceit, and at times, treachery by feigning civilian status or pretending to be enemy personnel.
As with peacetime espionage, captured spies may be prosecuted under the domestic law of a capturing State, and with similar laws in place or in an occupied territory. However, international humanitarian law (IHL) uniquely provides spies who rejoin their forces an entitlement to POW status and indicates they are not liable for their previous acts of espionage (Hague Regulations, art. 31). Such special protection extends to residents of occupied territory engaged in spying as well, as they are frequently agents controlled by State military and civilian intelligence organizations (AP I, art. 46).
Intelligence-based military and paramilitary operations are closely connected to the permissive legal regime governing espionage. Members of armed forces and civilians participating in hostilities without having lawful belligerent status were, until the Second World War, treated as war criminals. However, the extensive Allied employment of SOE, OSS, and Russian army and NKVD supported units led instead to their being called “unprivileged belligerents.”
It is not contrary to international law for States to employ such units. Although there are neither treaty recognition nor clear statements of customary international law regarding the status of “unprivileged belligerents,” the United Kingdom and the United States law of armed conflict manuals recognize the term (see here, para. 11.14, and here, para. 4.17). The U.S. Department of Defense Law of War Manual states: “[T]he law of war allows belligerents to employ spies, saboteurs, and other persons engaged in secretive hostile activities behind enemy lines” (para. 4.17.5). Unprivileged belligerents are treated like spies subject only to prosecution under the domestic law of a capturing State for their direct participation in hostilities (p.42).
From an international law perspective, it is primarily left to the prohibition against perfidy and the accordant war crime of treachery to restrict the actions of unprivileged belligerents. However, IHL only prohibits a relatively narrow range of perfidious acts such as: treacherously killing, wounding, and capturing an opponent while feigning civilian status; the use of poison; denying quarter; misusing uniforms and insignia (e.g., medical emblems, or the uniforms or insignia of neutral States, the UN, or enemy forces); and abusing a flag of truce. Many of these prohibitions are relevant to undercover operations, particularly in terms of feigning civilian status and wearing enemy uniforms.
It is perhaps more instructive to discuss what is not prohibited under international law. This includes: all espionage involving information gathering, whether in civilian or enemy disguise; acts of sabotage not involving perfidious killing or wounding; and for non-AP I countries, the treacherous capture of an opponent. Attempts at perfidious action have not gained recognition as a war crime, making the delict a result-based rather than conduct-based offence. Furthermore, the prohibition against the misuse of medical emblems and insignia does not extend to posing as medical personnel who do not display those emblems (although they would still be considered civilians. As I discussed in another post, factors such as remoteness and proximate cause further limit when perfidy constitutes a criminal act. Thus, the December 2024 remote triggering of a bomb-laden scooter planted by an Uzbek agent in Moscow, which killed Russian Lieutenant-General Kirillov, is unlikely to have met the elements of the crime of perfidy.
Added to the uncertainty of when operating undercover is problematic is the lack of consensus concerning when arms must be displayed openly prior to an attack. As an International Committee of the Red Cross Commentary to AP I notes regarding the Article 44(3) standard of “such time as visible to the adversary,” the drafting delegations could not agree whether this applied during “any movement toward a place from which an attack was to be launched,” “only a final movement to firing positions,” or “the moments immediately prior to an attack” (para. 1709). The circumstances under which the wearing of enemy uniforms or using their equipment is considered a war crime is itself open to interpretation and for non-AP I States is limited to engaging in combat. Two AP I States, Russia and Ukraine, have themselves reportedly worn each others’ uniforms or distinguishing signs as disguises in that conflict.
Another issue impacting what law applies to undercover operations during LSCOs is the requirement to govern occupied territory. An occupying power frequently employs military and civilian intelligence agencies and may use military and police undercover units during its counter resistance operations. However, governance in occupied areas is primarily maintained through law enforcement operations, which triggers the application of human rights law or human rights norms incorporated into the 1949 Fourth Geneva Convention. When employed in that role limits on the use of force by military units is not restricted by a “policy overlay,” but rather by law. Undercover operations are a regular and permissible part of law enforcement. Some operations, even against insurgents may be carried out using that tactic (see generally, here and here).
Other Sources of Legal Ambiguity
Significant legal ambiguity also arises because of fundamental legal disagreements about the exercise of State self-defence, when a resulting armed conflict begins and ends, and whether self-defence continues to apply throughout the course of a conflict. There are two interpretive approaches towards State self-defence. “Restrictionists” tend to “individualize” armed attacks, suggesting that hostilities only last while they are underway. The alternative “expansionist” approach, ascendant since 9/11, is more likely to accept that a series of attacks is part of a continuing armed conflict. There must be an armed conflict in existence for IHL to apply, and absent an armed conflict, international and domestic human rights law are the exclusive legal frameworks for assessing the legality of security operations.
Individualizing each armed attack could mean that peacetime human rights law applies between attacks, meaning any clandestine or covert killing of an opponent by one party for a public purpose would constitute assassination. Accountability would be left to the domestic judicial system of a targeted State, not unlike espionage generally. At the same time, States claiming there is an ongoing conflict would likely argue such targeting is lawful. It would only constitute assassination (and an international crime) if the killing resulted from a treacherous act, or if the target did not qualify as a lawful object of attack pursuant to IHL. Without a clear consensus on the existence of an armed conflict, the issue is in a considerable state of flux. The situation is further complicated by an erosion of the norm against assassination and a general lack of effort to hold States internationally accountable for such killing .
Problematically, scholars and practitioners rarely analyze the point at which an armed conflict resulting from an individual attack terminates. For example, given that a ceasefire only suspends hostilities, it is not clear how the June 2025 verbal ceasefire agreement could be said to have ended the “war” between Israel and Iran. Further complicating any analysis is the failure of the international legal community to reconcile the continued application of the law governing State self-defence and the existence of an ongoing armed conflict. While “overarching” and “limited” theories of continuing application have been suggested (p. 25), only recently have halting efforts emerged to address the issue (see here and here).
Significant legal disagreement, and therefore ambiguity concerning State self-defence, was on full display in the aftermath of Israel’s intelligence-enhanced attack on Iran. Various experts opined that it was illegal, colourably or arguably legal, and fully justified under international law. Elsewhere, it has been suggested there might be a new exception to the UN Charter’s general prohibition on the use of force under Article 2(4) that permits “forcible counterproliferation” as excusable, if not lawful, action. Consideration might also be given to the justifications provided by the United States, United Kingdom, and France for their 2018 strikes on Syrian chemical weapons sites: deterrence and promotion of regional stability; humanitarian intervention; and threats posed to humanity (p. 214-15).
Many of these diverse opinions are expressed with absolute certainty. However, an objective observer tasked with making these life-or-death defensive decisions might be excused if they consider themselves to be acting in a rather unsettled legal environment. The result is decision-makers have considerable flexibility in identifying the legal basis to justify a course of action. Added to this is the tendency of the international community to concentrate on major incidents while tending “to ignore less ‘high profile’ instances of inter-State recourse to force that do not result in public claims and often take place in unclear instances” (p. 179). Furthermore, States may prefer as a matter of policy to address the violence with a law enforcement response in preference to facing a larger conflict, even in cases where the threshold of an for armed attack may be met. As a result, there is considerable opportunity even during LSCOs for States to use intelligence-led operations below the level of conventional operations.
Conclusion
Notwithstanding a focus on conventional conflict, State reliance on intelligence-led military and paramilitary units, contract personnel, and agents to carry out operations in occupied territory or within an opponent’s territory is as relevant in the 21st-century’s LSCOs as during the Second World War. This irregular form of warfare is subject to the same legal frameworks as its conventional counterpart. However, several factors operate to facilitate such shadow conflict.
First, the lack of a clear consensus on the right to exercise State self-defence means States have greater freedom to rely on a legal interpretation that meets their strategic goals.
Second, the failure of the international community to fully address this form of warfare means the status of its participants remains unsettled. The same widescale use of espionage by States, which has led to a general acceptance of its use under international law, directly impacts on the status of these irregular warfare participants and the circumstances under which they might be held accountable. The use of personnel disguised to penetrate enemy territory to gather intelligence, carry out sabotage, and on occasion, kill an opponent, is as much a part of warfare as the large-scale movement of air, land, and sea formations.
Third, for States, the threat posed to States in this shadow conflict is much broader than the use of conventional forces. It involves threats hidden deep within the fabric of society. This, in turn, leads to a wider range of participants being involved to counter those threats. Reliance is placed not only on military forces, but also civilian intelligence and counterintelligence agencies, and police forces. IHL alone does not regulate their actions.
States and their “spy commandos” must held accountable for breaches of the law. The challenge for international law is that their widescale use by States, narrow definitions of perfidy, and the covert and clandestine nature of their operations make accountability difficult. As with espionage they are primarily regulated by the domestic laws of a capturing State. As can be seen in various investigations involving Canadian, UK, Australian, New Zealand, and U.S. special operations personnel, States recognize the need to regulate the activities of their own forces. This is particularly the case regarding allegations of the abuse or killing of captured personnel or uninvolved civilians.
Ultimately, the challenge is that intelligence wars take place in an environment shrouded in legal ambiguity regarding the status of its warriors, how undercover and other clandestine operations are carried out, and the strategic context in which they unfold. True accountability requires more attention to be redirected away from conventional conflict and the high-profile events that capture public attention towards these operations that occur shaded from public view.
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Ken Watkin served for 33 years in the Canadian Forces, including four years (2006-2010) as the Judge Advocate General.
The views expressed are those of the author, and do not necessarily reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense.
Articles of War is a forum for professionals to share opinions and cultivate ideas. Articles of War does not screen articles to fit a particular editorial agenda, nor endorse or advocate material that is published. Authorship does not indicate affiliation with Articles of War, the Lieber Institute, or the United States Military Academy West Point.
Photo credit: U.S. Army, Spc. Luke Sullivan
