All across Ukraine, ordinary citizens have been cornered into making a truly Draconian, but necessary choice: whether or not to take up arms and actively participate in defending Ukraine from Russia’s invasion—a mass escalation of the illegal war which started in 2014. People all over the country are heeding calls from the government and fellow citizens to defend their homeland, placing themselves at mortal risk to repel the Russian forces however they can.
From makeshift infantryman to digital warriors, resistance groups seem to be forming both organically and integrating into existing defense structures like the Territorial Defense Forces (TDF)—an organized, civilian volunteer corps that apparently forms part of the Ukrainian Armed Forces. In an extremely fluid and fast-evolving environment, assessing the status of these various resistance fighters under the law of armed conflict (LOAC) presents a near Sisyphean task with profound consequences.
Unfortunately, those assessments fall in the first instance to the Russian forces engaging with Ukrainians and there is little reason to believe they will approach them with a modicum of fealty to LOAC and its humanitarian ethos. Nevertheless, as this post explores, whether and how civilians join the hostilities bears directly on the protections they should be accorded under LOAC.
Combatant and Civilian Status under the Law of Armed Conflict
In an earlier contribution to this symposium, Ronald Alcala and Steve Szymanski laid out nicely a map of possible LOAC statuses that might apply to Ukraine’s so-called “resistance forces.” In short, they identify three general categories into which those actively participating in the on-going hostilities may fall: 1) Ukrainian armed forces; 2) resistance forces; and 3) civilian participants in a levée en masse. These categories roughly correspond to three different qualifications for combatant, which they further unpacked with greater detail, including some of the related implications for detention and targeting of those individuals.
Geoffrey Corn added to this discussion, addressing the status of these resistance forces in areas of Ukraine that fall under Russian occupation. As he noted, in addition to targeting and detention implications, accurate status determinations will (or at least should) bear on each individual’s entitlement to combatant immunity. Lawful combatants are shielded from prosecution for their participation in the hostilities, including acts of violence committed in accordance with LOAC.
The architecture of LOAC and its protective regimes are built on a schema of distinct categories of persons, dividing them neatly—at least in theory—into civilians, combatants, and non-combatants. Since at least the Treaty of Westphalia and the consolidation of the legal monopoly of violence in the sovereign, the law has recognized that with very limited exception, only members of a State’s armed forces, that is, “those by whose agency the sovereign makes war,” are imbued with the “privilege” to participate in hostilities. In return, only combatants benefit from the attendant immunity from criminal sanction for doing so. Civilians, on the other hand, lack this “privilege” to participate directly in hostilities and their life should thus be respected and protected.
To give maximal effect to its protective regimes, especially the cardinal principle of distinction (ICJ Nuclear Weapons Advisory Opinion, para. 78), LOAC seeks to draw a bright line between civilians and belligerents, with its greatest emphasis on protecting the former from the harmful effects of war. Civilians benefit from the most extensive array of LOAC protections, such as prohibitions on making them the object of attack, shielding them from maltreatment, and setting substantive and procedural limitations on internment or other restrictions on their liberty. Depending on the circumstances, they receive the full panoply of protections contained in the Fourth Geneva Convention (GC IV).
Notwithstanding the central importance of civilian protection to LOAC, no treaty defined the term until its inclusion in the 1977 Additional Protocol (AP I) to the 1949 Geneva Conventions—an instrument to which both Ukraine and Russia are parties. Article 50 provides a negative definition of civilian—that a civilian is any person not falling within the categories of persons “referred to in Article 4(A)(1), (2), (3) and (6)” of the Third Geneva Convention (GC III) (a subset of those entitled to prisoner of war (POW) status) and in Article 43 of AP I (defining armed forces of a Party to the conflict)(emphasis added).
In other words, combatants are essentially members of organized armed groups (OAG)—armed forces, militias, volunteer corps, and resistance movements—sanctioned by and operating as agents of a State Party to a conflict, whereas civilians are anyone other than combatants (and possibly unprivileged belligerents). Article 50 also provides that in case of doubt as to whether someone is a civilian, that person shall be considered to be a civilian. Although the United States does not consider this presumption to be a part of customary international law, Russia and Ukraine are bound by the treaty provision.
But are these categories as distinct and seamless as they appear at first blush, and do they sufficiently reflect the realities of modern warfare? Or do the amorphous and rapidly changing circumstances on the ground in Ukraine expose gaps and seams in the LOAC status framework? Ukrainian civilians are taking up arms to defend their homeland in ways and numbers we have not seen since at least the Second World War. Unsurprisingly, they are doing so in myriad ways—actions such as physically blocking vehicles and convoys, building barricades, preparing Molotov cocktails, and engaging in direct combat, as well as reportedly conducting cyber operations. Add to this fog the involvement of external actors, such as Microsoft, Anonymous and other hacktivists, and the lines quickly get blurry.
With mounting evidence of Russian war crimes, and its penchant for seeking to paper over its violations with LOAC-couched propaganda, it’s highly likely that Russia will seek to exploit these gaps and seams to its advantage and to the detriment of those resisting them.
Transforming from Civilians to Belligerents
In recognition of the realities of warfare, the broad protections afforded civilians are not absolute. They are conditioned on civilians refraining from participating directly in the hostilities. When civilians breach this condition, it fundamentally changes the protective regimes they benefit from. Exactly how and to what degree will depend on what actions they take, and whether they take such actions with the sanction of a Party to the conflict.
Civilians Directly Participating in Hostilities
As set out in Article 51 of AP I, it is prohibited to make civilians—individually or collectively—the object of attack, “unless and for such time as they take a direct part in hostilities.” That is, civilians directly participating in hostilities (DPH) may be targeted, and under prevailing views, need not be accounted for in a proportionality analysis or when applying AP I, Article 57 precautionary rules. If captured, subject to certain minimal treatment standards and due process set out in Article 75 of AP I, and where applicable, Article 78 of the Fourth Geneva Convention, directly participating civilians can be detained and prosecuted for their actions.
Notwithstanding these considerable implications, AP I is notoriously silent on both the substantive and temporal meaning of this exception. The exact contours of the DPH exception, both as to the specific meaning of “direct participation” and the temporal parameters of the rule, have been and remain the subject of intense debate. Despite the prominence it has played in the conflicts of the last twenty years, efforts to bring greater clarity to the rule, such as the ICRC’s Interpretive Guidance on the Notion of Direct Participation in Hostilities, have made limited headway. For example, according to the U.S. Department of Defense Law of War Manual, “the United States has not accepted significant parts of the ICRC’s interpretive guidance as accurately reflecting customary international law.” (§ 188.8.131.52.).
The parameters of the debate are beyond the scope of this post. Some acts, such as attacking Russian forces with Molotov cocktails, present obvious DPH cases. Others, like building obstacles or blocking convoys are less clear. And as seen in the commentary to Rule 97 of the Tallinn Manual 2.0, applying the rule to non-State cyber actors will prove even more complex. Suffice to say that the challenges of applying this unique conduct-based targeting authority are only exacerbated in the present situation where civilians are under direct assault on a mass scale and forced to take exceptional measures to defend themselves and their nation. Of course, whether an individual is engaged in direct participation is only relevant if he or she does not qualify as a combatant or, as set out below, a non-State OAG.
Levée en Masse
The Ukrainian populace’s mass resistance to Russia’s invasion has resurrected a near-dormant aspect of LOAC—the concept of the levée en masse. Pursuant to Article 4(A)(6) of GC III, “[i]nhabitants of a non-occupied territory who, on the approach of the enemy, spontaneously take up arms to resist the invading force” are considered combatants, can be targeted as such, and are entitled to POW status and combatant immunity if captured. As recognized in the 2020 Commentary to GC III, this is a unique category of combatant, “as it is the only group of persons recognized under Article 4A with full autonomy from the State.” (para. 1062). That is, unlike all other categories of combatant, members of a levée do not act under State sanction or authority.
Also, in an obvious nod to the in extremis circumstances that would necessitate such armed resistance, levée combatants are subject to minimal qualifying conditions. They need only carry their arms openly and respect the laws and customs of war. The absence of the more stringent criteria found in Article 4A(2) of GC III—that of having a fixed distinctive sign and being commanded by a person responsible for subordinates—raises clear risks to the principle of distinction and command accountability.
Owing to these risks, as Alcala and Szymanski note, it is generally considered a disfavored category, and some have argued, at least prior to current events, that in the age of modern warfare it is obsolete. Perhaps presciently, the 2020 Commentary pushes back on those suggestions, noting that “practice has suggested that even in circumstances where the invading force employs advanced military technology, the approach of an invading army could still prompt civilians to take up arms against it.” (para. 1063). Still, because of its unique, autonomous nature, the conditions allowing for a true levée are limited, and can rapidly dissipate as the circumstances change, some of which are beyond the participants’ control.
As a factual matter, the element of spontaneity presents a challenge in the present circumstances. By any objective measure, Russia and Ukraine have been engaged in an ongoing armed conflict since 2014. Ukrainians have been organizing themselves to varying degrees to deal with that reality for some time, and Vladimir Putin began signaling his intentions with demands, threats, and a substantial troop buildup at least as far back as December 2021. From the outset, President Zelenskiy has called on Ukrainian citizens to fight and the government has distributed thousands of weapons.
Further, as Geoffrey Corn detailed, once Russian forces enter a state of occupation (even partial occupation), resistance forces in occupied territories can no longer lay claim to levée status. In either case, their entitlement to combatant status and immunity will then depend on whether they belong to groups sufficiently formed, organized, and sanctioned by the State to qualify under Article 4A(2) of GC III and Article 43 of AP I, as will be further discussed below.
Regardless, if some in the resistance “did not have sufficient time to organize themselves in advance [of the current invasion] in conformity with the conditions of Article 4A(2)” (2020 Commentary, para. 1066), it’s apparent that many have been hastily doing so to varying degrees and likely with mixed adherence to the Article 4A(2) criteria. So, assuming these individuals qualified as levée combatants at some point, once they begin forming into OAGs, what is the impact on their combatant status? If they fail to fully meet the 4A(2) criteria, do they revert back to civilians, possibly engaging in DPH, or do they transition into the controversial status of unprivileged belligerents?
Organized Armed Groups and the Netherworld of Unprivileged Belligerency
In 2002, the terms “unlawful combatant” and “unprivileged belligerent” entered the LOAC lexicon with vigor when President George W. Bush made a blanket determination to deny POW status to all captured Taliban personnel, notwithstanding the fact that GC III applied to the initial phases of U.S. combat operations in Afghanistan. The U.S. position and practice since has been that non-state OAGs, even those operating in the context of an international armed conflict, are non-civilian belligerents that may be targeted based on their status as such, can be detained for the pendency of the conflict as a lawful incident of warfare, and subject to prosecution for their participation in the hostilities (See, e.g., DoD Law of War Manual, § 5.8.2). The position is not without legal fundament. Nevertheless, debates over the validity and implications of designating members of non-state OAGs as neither civilians nor “lawful” combatants have continued since.
Given the chaotic circumstances on the ground, it is unclear whether all of the resistance groups forming in Ukraine are aware, let alone capable of, adhering strictly to the four criteria set out in Article 4A(2)(a) through (d) of GC III to qualify as combatants. Recall that it was the Taliban’s failure to meet these criteria that was cited as the basis for categorically denying them POW status in 2002. As a State Party to AP I, Russia is bound by Article 44(3), which might provide some relief for otherwise non-compliant OAGs in that it eases the obligation of combatants to distinguish themselves where they cannot do so owing to the nature of the hostilities. However, the scope of Article 44(3) application is uncertain. It was and remains a controversial provision of AP I, one that substantially contributed to the U.S. decision not to ratify the treaty and caused several States (although not Russia) to file reservations that would limit its applicability.
Additionally, to qualify for the “right” to engage in hostilities, an OAG must belong to a Party to the conflict, i.e., be operating under the sanction of, and as agents for the government of Ukraine. For resistance forces that have not been officially incorporated into the Ukraine armed forces, such as the TDF (see Article 4A(1) of GC III), to qualify as combatants, they “must in fact fight on behalf of” Ukraine, which itself “must accept both the fighting role of the group and the fact that the fighting is done on its behalf.” (2020 Commentary, para. 1005).
While the bar is not particularly high—Ukraine’s “acceptance” can be tacit and manifested in different ways—“[i]t is essential that there should be a ‘de facto’ relationship between the resistance organization” and the Ukrainian government. (1960 Commentary, p. 57). President Zelensky has certainly called for and encouraged active resistance and is unlikely to disavow those responding to those calls. However, whether a de facto relationship exists for each OAG forming in the melee of the conflict is a factual matter—one that Russia could seek to exploit to its advantage.
Pointing to the strict dichotomy between civilians and combatants adopted under Article 50 of AP I, Alcala and Szymanski note that as a State Party to AP I, Russia may not have the option of treating resistance fighters as unprivileged belligerents. They must be considered either combatants or civilians subject to the consequences of directly participating in hostilities (with the complicating factor of the temporal limitations of the DPH rule as applied to those who frequently or continuously engage in resistance activities). However, as noted in the 2020 Commentary to GC III (para. 1002), the requirement that combatant OAGs belong to a Party reflects States’ “continued interest in ensuring that the status of ‘lawful combatants’ was not extended to persons engaged in private wars,” and it is unclear from the text of AP I, its drafting history, and the 1987 Commentary that States Parties intended to eliminate this historically recognized category of belligerents.
Suffice to say that this is an open question, and given the designation of certain OAGs as unprivileged belligerents in recent conflicts, it is quite possible that Russia will apply the Article 4A(2) criteria stringently and treat those resistance forces not strictly meeting them as unprivileged belligerents if captured.
Why Does It Matter?
At first blush, it is a fair question whether any of this matters. As the DoD Law of War Manual notes, for purposes of targeting, whether resistance forces are considered civilians directly participating in hostilities or unprivileged members of an OAG, the consequence is essentially the same: “[both civilians directly participating in hostilities and] members of hostile, non-State armed groups may be made the object of attack unless they are placed hors de combat.” As U.S. experience over the last two decades has borne out, this may be true as a practical matter at the level of tactical combat engagements. But it is a misleading overstatement. Unlike members of a belligerent force, civilians are presumed inoffensive and shielded from attack, unless they engage in specific, identifiable conduct that temporarily strips them of that protection. This is a far-more constrained targeting authority than the quote above implies, and certainly in the context of deliberate targeting decisions, placing an individual on a strike list requires different, and periodically updated validation of continued targetability.
Where resistance forces fall into the hands of Russian forces, the consequences of these status determinations can be significant. As noted several times, as POWs, captured combatants benefit from the full array of protections set out in GC III. And although they are entitled to only minimal due process for determining whether they in fact qualify as POWs in accordance with Article 5 of GC III, and may be held without trial for the pendency of the conflict, they benefit from the shield of combatant immunity.
In contrast, whether captured and held as civilians who directly participated in hostilities or as unprivileged belligerents, resistance forces can be criminally tried and subjected to severe penal sanction. However, designation as the latter would not only allow Russia to hold them without charge for the pendency of the conflict, it would also deprive them of the specific protections of both GC III and GC IV, including Article 78’s internment standards and procedures. Russia would be bound only by the minimum humane treatment standards of Common Article 3 to the 1949 Geneva Conventions, and the slightly more robust protections of Article 75 of AP I. If history is any guide, these are malleable guardrails that Russia will at best manipulate, and at worse ignore, to the detriment of captured Ukrainians.
The Ukrainian citizens taking up arms to repel Russia’s aggression understand all too well the risks they are taking. That they may not fit neatly into one of the theoretically distinct categories outlined above is presently the last thing on their minds. But the consequences of the decisions Russia chooses with respect to its LOAC obligations are significant. As Ukrainians continue to organize and resist, they should take all feasible measures to comply with the requirements to qualify as lawful combatants and thereby deprive Russia of any arguments for treating them otherwise. And the world should pay close attention and hold Russia to account.
Gary Corn is the Director of the Technology, Law & Security Program and Adjunct Professor of Cyber and National Security Law at the American University Washington College of Law.
 Emmerich de Vattel, The Law of Nations, bk. III, ch. II, § 6 (Joseph Chitty ed., 1834) (Gaunt reprint 2001) (1758)).
 It is by no means the author’s intent to equate the Ukrainian resistance fighters with the Taliban, only to point out the precedent of a State denying an OAG combatant status based on failure to meet Article 4A(2) criteria.
Photo credit: Ministry of Internal Affairs of Ukraine (mvs.gov.ua)