GC IV Commentary Series – Navigating the Complexities of Common Article 3

Editors’ note: The following series considers ICRC’s 2025 updated Commentary on the Fourth Geneva Convention. Rosa-Lena Lauterbach, Liisi Adamson, and Sean Watts’s introduction to the series is available here.

The delegates who drafted the 1949 Geneva Conventions described common Article 3 (CA 3) as a “Convention in miniature.” In a very real sense, the 2025 Commentary to the Fourth Geneva Convention (the 2025 Commentary) can be described as the accordant “Commentary in miniature,” because of its comprehensive and highly beneficial account of CA 3. The drafters of the 2025 Commentary tackled one of the most complicated aspects of this update. Indeed, it is probably no exaggeration to say that the interpretation and evolution of no other article of the Conventions has been more consequential than that of CA 3. While largely identical to the text in the 2016 revision of the Commentary to the First Convention, its significance and value are beyond doubt.

That significance derives primarily from an undeniable historical anomaly: CA 3—among hundreds of Convention articles, the only one devoted to armed conflicts not of an international character—addresses what became the dominant type of armed conflict since 1949. Thus, while the drafters of the Conventions focused principally on enhancing the regulation of international armed conflicts, their brief foray into the realm of non-international armed conflicts has garnered outsized significance as the world has and continues to grapple with the humanitarian challenges in a wide array of situations falling outside the international armed conflict category.

Defining the situations to which CA 3 applies has profound consequences. Not only will it impose the obligation to comply with the article’s humanitarian mandate, but it will also be viewed as justifying the invocation of authorities derived from the law of armed conflict. As noted in the Commentary,

[T]he wording agreed upon does not resolve the persistent question of the scope of application of common Article 3. The intentional lack of detail on this point may have facilitated States’ adoption of common Article 3. However, clarity as to its scope of application is important, as whether or not a given situation is an “armed conflict not of an international character” entails significant consequences (para. 458).

It certainly does.

Indeed, it is naïve to ignore the reality that States perceive the obligation to comply with CA 3’s humanitarian provisions as opening the door to the lawful use of military power beyond what is permitted outside armed conflict. And, according to the Commentary, that view is understandable, “[w]hen common Article 3 is applicable, other rules of international humanitarian law, including those on the conduct of hostilities, with different restraints on the way force may be used compared to peacetime law, also apply” (para. 542). This includes: the authority to employ lethal force as a measure of first resort; the authority to employ such force based on status determinations and not the threatening conduct of the object of “attack”; the authority to detain captured enemy personnel for the duration of hostilities; and perhaps the authority to utilize extraordinary military tribunals to sanction alleged violations of the laws and customs of war by those same captives.

In actuality, the article was never intended to bring into force anything other than humanitarian obligations – it simply indicates the humanitarian obligations applicable in the event of an armed conflict not of an international character. Nonetheless, it has evolved into something akin to a non-international armed conflict quasi ad bellum. And thus, it should come as no surprise that the Commentary offers important insight into this broader question: what indicates the existence of a “CA 3” armed conflict?

The 2025 Commentary’s CA 3 Two-Part Test

Like the 1958 Commentary, the 2025 update addresses the widely accepted meaning of the situations to which CA 3 applies. This includes a comprehensive—and highly beneficial—review of how the meaning of non-international armed conflict evolved since 1949, when these four treaties were opened for ratification. This review draws on CA 3’s original motivation, international tribunal jurisprudence, and State practice.

The 1958 Commentary explained that the Diplomatic Conference of 1949 intentionally chose not to define “armed conflict” because the delegations feared that a rigid definition or a list of obligatory conditions would restrict application of this important new humanitarian provision. Instead, the Commentaries on the Geneva Conventions published by the ICRC under the general editorship of Jean Pictet listed several “convenient criteria” for assessing common Article 3’s applicability. As these Commentaries noted, these criteria were drawn from the amendments discussed during the 1949 Diplomatic Conference. The Commentary to the Fourth Convention noted that these criteria were considered neither cumulative nor obligatory but instead provided a “useful … means of distinguishing a genuine armed conflict from a mere act of banditry or an unorganized and short-lived insurrection” (p. 36). The 2025 Commentary builds on its predecessor, noting that, “over time, of the criteria enumerated in the Pictet Commentaries, two are now widely acknowledged as being the most relevant in assessing the existence of a non-international armed conflict: that the violence has reached a certain intensity and that it is between at least two organized Parties/armed groups” (para. 492).

Perhaps time and experience merely clarified these two criteria as the most relevant and significant, or perhaps the international legal community drifted towards the very rigidity Pictet sought to avoid. Nevertheless, by emphasizing the special significance of these two considerations, the Commentary reflects the so-called Tadić test. This is unsurprising, as that decision by the International Criminal Tribunal for the Former Yugoslavia was, up to that time, the most comprehensive judicial analysis of the meaning of armed conflict not of an international character; an analysis almost universally considered authoritative. Its centrality in the Commentary’s discussion bolsters that conclusion.

Today’s Wars – “Fighting at the Legal Boundary”

This Tadić test is increasingly significant given the range of contemporary non-State threats States confront. This is because it accommodates State security interests while delegitimizing overbroad assertions of armed conflict to justify excessive uses of “wartime” authority, most notably lethal force. The importance of this conflict assessment framework is highlighted by the Commentary’s recognition that the Conventions’ drafters likely did not anticipate today’s organized non-State armed groups operating from war-torn countries or ungoverned areas. The Commentary notes that in 1949 the article was focused almost exclusively on “internal” armed conflict: contests between State authorities and non-State armed groups seeking either separation from the State or to oust authority and take control of the State. Such armed conflicts still occur. However, the Commentary also acknowledges the post-1949 evolution of “conflicts not of an international character” in ways that have deviated from this norm.

According to the Commentary, a primary example of this post-1949 evolution is what it characterizes as “spill-over” hostilities: when an “internal” armed conflict spills over into the territory of a neighboring State. Mirroring its 2016 predecessor, the Commentary goes further and tentatively wades into the realm of “transnational” armed conflicts or “internationalized” non-international armed conflicts: hostilities between State forces and organized non-State armed groups operating either in both State territory and transnationally, or even exclusively transnationally without the host State’s involvement. According to the 2025 Commentary, “Non-international armed conflicts with an extraterritorial aspect have been described variously as ‘cross-border’ conflicts, ‘spillover’ conflicts and ‘transnational armed conflicts’. Other terms, such as ‘extraterritorial non-international armed conflicts’, have also been used. These are not legal categories or terms, but they may be useful for descriptive purposes” (para. 546).

Aligning with State practice, the Commentary rejects a restrictive interpretation of CA 3’s scope based on the article’s plain text, which indicates it applies to conflicts not of an international character occurring “within the territory of a High Contracting party.” By acknowledging the article’s applicability to such extraterritorial NIACs, the Commentary reflects the article’s pragmatic objective: to ensure basic humanitarian protections apply to any situation of armed conflict that does not qualify as international within the meaning of common Article 2 (CA 2) of the Conventions. Any other interpretation would open the door to assertions of authority derived from the law of armed conflict while disavowing humanitarian obligation, the interpretation adopted by the United States in relation to captured al Qaeda and Taliban personnel until the U.S. Supreme Court interpreted CA 3 to align with what is now reflected in the Commentary.

Specifically, the Commentary explains,

At first sight, the wording of common Article 3 requires such a limitation: not only does it speak of armed conflicts “not of an international character”, but it also requires armed conflicts to occur “in the territory of one of the High Contracting Parties”. One reading of this phrase could be that the conflict must occur in the territory of precisely “one” of the High Contracting Parties, thereby limiting the application of common Article 3 to “internal” armed conflicts. However, another reading could put the emphasis on the fact that the conflict must occur in the territory of one of the “High Contracting Parties”, thereby merely excluding conflicts which occur on the territory of a State not party to the Geneva Conventions. Common Article 2 likewise contains a reference to the States party to the Geneva Conventions. Viewed in this context, the reference to “High Contracting Parties” in both articles may have been included to avoid any misunderstanding to the effect that the 1949 Geneva Conventions would create new obligations for States not party to them. With the universal ratification and applicability of the 1949 Geneva Conventions, there are now no States that are not parties to them.

The object and purpose of common Article 3 supports its applicability in non-international armed conflict reaching beyond the territory of one State. Given that its aim is to provide persons not or no longer actively participating in hostilities with certain minimum protections during intense armed confrontations between States and non-State armed groups or between such groups, it is logical that those same protections would apply when such violence spans the territory of more than one State (paras. 540-41)

The Commentary then emphasizes what is operationally a simple yet profoundly important premise, namely, that those using the tools of war must acknowledge the binding nature of rules of war.

When common Article 3 is applicable, other rules of international humanitarian law, including those on the conduct of hostilities, with different restraints on the way force may be used compared to peacetime law, also apply. It is not the applicability of common Article 3 to a situation that makes other rules of international humanitarian law governing non-international armed conflicts applicable. Rather, it is the existence of a non-international armed conflict which makes common Article 3 and other international humanitarian law provisions applicable. Viewed in this light, it is consistent with the purpose of common Article 3 for it to apply to non-international armed conflicts that are not confined to the territory of a single State (para. 542).

Any other interpretation would allow States to follow the same incongruous approach that defined the initial phases of the U.S. armed conflict against al Qaeda. As noted above, this problematic restrictive interpretation ended only after the U.S. Supreme Court held in Hamdan v. Rumsfeld that CA 3 applied in “contradistinction” to CA 2, meaning once the United States asserted the authority to detain captives derived from a situation of armed conflict, it was bound by the obligations established by CA 3. The Commentary reflects the Hamdan Court’s approach.

A Missed Opportunity?

It is apparent that not much changed in the Commentary from its 2016 predecessor. A side-by-side comparison showed mainly grammatical or sourcing differences. This feels like a lost opportunity to consider the influence of State practice on the evolution of NIAC during that decade; a decade that included major combat operations against non-State organized armed groups like ISIS, the Houthis, Hamas, and Hezbollah, to name a few. This would have been especially informative regarding the applicability and efficacy of the Tadić two-part test to transnational or extraterritorial NIAC situations.

The prevalence of this type of NIAC since the publication of the 2016 Commentary coupled with the repetition of the 2016 version does not negate the importance of the Commentary’s primary focus on international tribunal jurisprudence. Unfortunately, it does seem to reflect a seemingly tentative acknowledgment the notion of transnational NIAC and a reluctance to acknowledge the realities of contemporary non-State threats. Overlooking military operations responsive to these threats does not necessarily lead to greater application of humanitarian treatment. Indeed, it could be argued that the apparent reluctance to provide a more extensive analysis of whether and when such operations qualify as armed conflicts subject to CA 3 and other international humanitarian law obligations subtly contributes to highly contestable assertions of armed conflict, such as those related to the U.S. counter-narcotics operations off the coasts of several South American nations.

This, in turn, begs an important question: who is the primary audience of this revised Commentary? Is it the international legal community (a community that covets certainty and legal predictability)? Or is it the States that must make complicated decisions on how to characterize a security threat response and what obligations it must comply with during that response? Ultimately, it must be the latter, for as the Commentary notes, no supra-national organ or tribunal adjudicates whether, when, and where a State may invoke the authorities and obligations inherent in armed conflict.

Assessing where the Tadić and Pictet methodologies align in relation to this legal boundary and the realities of transnational non-State threats therefore remains highly significant. This is not to suggest that the Commentary fails to offer useful guidance on this conflict-assessment issue. On the contrary, the comprehensive articulation of various legal assessments of armed conflict supports several critical conclusions. First, CA 3 does not define armed conflict; armed conflict occurs first and triggers CA 3. Second, a State’s choice to apply CA 3’s humanitarian obligations to a given situation does not ipso facto legitimize the methods the State employs.

Concluding Thoughts

Ultimately, the Commentary’s value is inevitably linked to how effectively it advances the core interests of international humanitarian law writ large: ensuring a rational balance between the security interests of States and protecting victims of responsive operations from overzealous assertions of combat power or deprivation of fundamental humanitarian protections. Pictet’s totality approach, framed by useful considerations, seemed to respond to this. The Commentary builds on this and, while not perfect, will hopefully contribute to the legitimate, effective, and pragmatic implementation of humanitarian law.

***

Geoffrey S. Corn is the George R. Killam, Jr. Chair of Criminal Law and Director of the Center for Military Law and Policy at Texas Tech University School of Law and a Distinguished Fellow at JINSA Gemunder Center for Defense & Strategy.

Benzion Aron is a 2026 graduate of Texas Tech University School of Law and a fellow at the school’s Center for Military Law and Policy.

The views expressed are those of the authors, 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. Navy, Navy Petty Officer 2nd Class Nathaly Cruz