When does violence between a state and non-state actor constitute an armed conflict and thus trigger the system of legal rules that apply in non-international armed conflict (NIAC)? That question has been at the core of law and policy debates—since the drafting of the 1949 Geneva Conventions, and reinvigorated by a series of legal issues post September 11th.  Many believe that the law of armed conflict, when it is applicable, displaces as lex specialis some of the protections afforded by otherwise applicable international human rights law and that application of the law of armed conflict to a given situation thus introduces a “more permissive” set of legal rules for the use of lethal force. Others believe that, in some situations, the law of armed conflict is the only potential source of international law imposing meaningful restrictions on the use of force, detention power, and other measures, and thus that application of the law of armed conflict is, in effect, restrictive. In other words, the stakes are quite high. On our view, however, current discussions of this topic are incomplete, and we thus offer our analysis here as a corrective.

I. Two Competing Positions

The competing perspectives on this issue can be boiled down to two major positions. A prominent view holds that violence between a State and a non-state organized armed group must reach a significant level of intensity to constitute a NIAC. This position was recently expressed by the International Committee of the Red Cross (ICRC) in its new commentaries on the Geneva Conventions.  An alternative view, recently expressed by Professor Adil Haque in a Just Security post, is that the intensity of violence should not be a precondition for the existence of a NIAC. Rather, he argues that “if an organized armed group has the capacity to sustain military operations then any military operation by or against that group should be constrained by the law of armed conflict.”

Although we have some reservations to embracing a “capacity”-based standard and we have our own opinions about whether or to what extent the law of armed conflict displaces human rights law, like Prof. Haque, we use the 2016 Commentary as a point of departure. To supplement his normative analysis, we dive into some of the legal authorities on this topic.

II. Tadić‘s Pedestal

An almost sacred text for those who favor the ICRC position is the jurisprudence of the International Criminal Tribunal for the former Yugoslavia and, in particular, that court’s landmark judgment, Tadić v. Prosecutor. It is true that Tadić supports the proposition that the intensity of the conflict is an essential element for determining whether a NIAC exists, but is the Tadić approach necessarily applicable in cases outside of its particular context? As one of us has argued elsewhere (see note 202), there are reasons to doubt whether the Tadić test is applicable for other types of determinations.

There may be two types of NIAC determinations: de facto and de jure (thanks to our former colleague Michael d’Annunzio for this conceptual framework).  Both involve an assessment of actions by prospective parties.  The judgment in Tadić and similar jurisprudence by international tribunals embody the de facto approach, under which the existence of an armed conflict is judged retrospectively according to objective facts such as the intensity of the fighting.  The de jure approach may accept that law of armed conflict obligations attach immediately when parties intentionally resort to armed force, even if Tadić’s intensity threshold was not met prior to that resort to armed force.

In Tadić and similar jurisprudence by international tribunals, the position of the judicial body and the parties before it is relevant to the construction of decision-rules and interpretative approaches. As an evidentiary matter, a tribunal may need to look to objective indicia such as scale of armed activity to determine whether a NIAC exists. The Tadić approach was, indeed, developed in a particular situation in which a member of a state party to a conflict challenged the jurisdiction of the international tribunal by denying that certain alleged conduct occurred in the context of armed conflict–an element of the Tribunal’s jurisdiction. That is very different from a situation in which a state party proclaims itself to be in an armed conflict at the outset.

There may also be a special qualitative difference in the international criminal context. In judgments by a supranational tribunal deciding on criminal liability, good reasons exist for an objective method for determining the existence of an armed conflict. Consider in particular the historical context of Tadić and the issues facing those judges. The Government of the State whose officer’s conduct was at issue, the Socialist Federal Republic of Yugoslavia, had effectively dissolved, and the accused officer stood to escape criminal liability for his conduct by denying that his actions occurred in the context of armed conflict.  At the same time, it was a controversial move for the ICTY to conclude that certain violations of the laws of war in a NIAC (namely, breaches of common Article 3 of the Geneva Conventions) incur international criminal liability. Indeed, the States that drafted and ratified the Geneva Conventions never envisioned such a result. On the contrary, they thought there was little, or far less, consequence to their design of common Article 3 of the Conventions: a minimum core of the most fundamental norms that the parties would apply in the broadest possible circumstances of armed conflict not of an international character. That grand bargain in 1949—minimalist substantive obligations accepted as regulations in a broad set of conflicts that previously were largely regulated only by the sovereign—is why the scope of NIAC under treaty law would presumably involve a low or nominal threshold, but under CIL for criminal liability there may be a higher one.

At the very least, there should be a burden on those who want to transpose the “Tadić test” onto determinations of the existence of NIAC for purposes beyond the specific jurisdictional and criminal law concerns of an international war crimes tribunal. That additional analysis is especially necessary when the transposition is onto interpretations—like the ICRC’s 2016 commentaries—that concern the threshold for common Article 3 conflicts as a matter of treaty law.

III. Contrary Authority

Using the ICRC’s 2016 Commentaries as a point of departure, it is remarkable the degree to which this particular section of the new commentaries overlooks contrary authority. The 2016 Commentary suggests that its interpretation of the NIAC threshold reflects an essentially unbroken line of authority from the 1949 Geneva Conventions to the present (see, for example, para 435).We do not attempt to reconcile the competing sources of authority with the ones discussed by the ICRC. We believe it is a sufficient contribution here just to highlight the other sources, which stand as counterexamples to the Tadić /ICRC line of thinking.

Some of these examples are specific to the interpretation of Common Article 3. Others are more generally about the threshold of application of jus in bello under customary international law. Both types of examples are relevant to the issue as discussed in the 2016 Commentaries.

1. Pictet Commentaries

The original ICRC Commentaries on the Geneva Conventions—the so-called Pictet Commentaries—list “convenient criteria” for assessing the applicability of Common Article 3. Important examples on the list do not necessarily or expressly require a specific level of intensity of violence:

(1) “[t]hat the de jure Government has recognized the insurgents as Belligerents;” and

(2) “[t]hat the dispute has been admitted to the agenda of the Security Council or the General Assembly of the United Nations as being a threat to international peace, a breach of the peace, or an act of aggression.”

In general, the list of criteria suggests that States have significant discretion in concluding for themselves that an armed conflict to which Common Article 3 applies exists (the de jure approach we described above). And, in terms of how low the bar was set, it is important to recall that the Pictet Commentaries stated, in strong terms, that none of the criteria were required for the existence of a Common Article 3 conflict:

“Does this mean that Article 3 is not applicable in cases where armed strife breaks out in a country, but does not fulfil any of the above conditions (which are not obligatory and are only mentioned as an indication)? We do not subscribe to this view. We think, on the contrary, that the Article should be applied as widely as possible. There can be no reason against this.” (emphasis added)

Professor Derek Jinks also usefully described the breadth of these criteria in the context of the negotiating history of the Geneva Conventions:

“[T]he criteria themselves are pitched in general terms and should be interpreted broadly. In short, the criteria are best understood as independently sufficient grounds to establish the existence of an ‘armed conflict.’ Indeed, the drafting history of Common Article 3 supports this conclusion. The list of criteria closely tracks an influential amendment offered by the Australian delegation at the Diplomatic Conference. And this amendment plainly forwarded the criteria as alternative modes of establishing the existence of an armed conflict.”

2. International Court of Justice

In the Nuclear Weapons Advisory Opinion (1996), the International Court of Justice (ICJ) stated a proposition which may be read to mean that a State’s use of armed force, such as highly destructive weaponry, in the exercise of self-defense will have to comply with the law of armed conflict. The Court stated: “a use of force that is proportionate under the law of self-defense, must, in order to be lawful, also meet the requirements of the law applicable in armed conflict which comprise in particular the principles and rules of humanitarian law.” Notably, the U.S. Department of Justice’s Office of Legal Counsel (OLC) appears to have read this passage accordingly. In 2010, the OLC provided the following description of the ICJ opinion: “fundamental law-of-war norms are applicable even where military force might be employed outside the context of an armed conflict, such as when using powerful weapons in an act of national self-defense.”

3. Court of Justice for the European Union

In 2014, the Court of Justice for the European Union addressed the criteria for determining the existence of an internal armed conflict. The case involved protections for refugees, and compelled the Court to interpret an undefined term—“internal armed conflict”—in the relevant EU Directive. The Court held that the intensity of violence was not an essential criterion for the existence of an internal armed conflict. The Court stated:

“Consequently, the answer to the question referred is that, on a proper construction of Article 15(c) of Directive 2004/83, it must be acknowledged that an internal armed conflict exists, for the purposes of applying that provision, if a State’s armed forces confront one or more armed groups or if two or more armed groups confront each other. It is not necessary for that conflict to be categorised as ‘armed conflict not of an international character’ under international humanitarian law; nor is it necessary to carry out, in addition to an appraisal of the level of violence present in the territory concerned, a separate assessment of the intensity of the armed confrontations, the level of organisation of the armed forces involved or the duration of the conflict.”

How should we understand the Court’s holding with respect to broader understandings of the definition of internal armed conflict? In a Just Security post, Professor David Luban wrote:

“The Court is focusing, of course, on a very special context: the eligibility of people fleeing violence for legal protection against being sent back into the situation they were fleeing. It’s an inquiry tailored to the individualized threat the person faces, and the Court doesn’t purport to be giving an all-purpose definition of ‘internal armed conflict.’ Nevertheless, it’s a noteworthy decision that could ultimately have an impact on the definitions of armed conflict in IHL.”

4. United States

The OLC Opinion referenced above cited the ICJ Advisory Opinion in support of the OLC’s own analysis. The Department of Defense’s 2015 Law of War Manual clearly articulates a low threshold for application of the law of armed conflict and it makes no distinction between international armed conflict and NIAC in this formulation. It states:

3.4.1 Intent-Based Test for Applying Jus in Bello Rules. Jus in bello rules apply when a party intends to conduct hostilities.

If a State chooses to go to war, then it is bound by jus in bello rules for the conduct or those hostilities. For example, if a State considers it necessary to respond to attacks with military force, then those military operations must comply with jus in bello rules.

The fact that the intention to conduct hostilities gives rise to obligations to comply with the law of war is important because law of war obligations must be taken into account even before the fighting actually begins, such as in the planning of military operations.

Notably, the 2016 Commentaries cite the DoD Law of War Manual in the discussion of other topics, but not this one.

One caveat of note: The Law of War Manual qualifies the above analysis by stating that it applies to jus in bello restrictions, and not necessarily jus in bello permissions: “It must be emphasized that the discussion in this section is for the purpose of assessing whether jus in bello restrictions apply and not necessarily for other purposes. … Similarly, the fact that jus in bello restrictions apply is not determinative of whether the permissions that are sometimes viewed as inherent in jus in bello rules may be relied upon by a State or non-State actor.”

5. The United Kingdom

The U.K. Secretary of State for Defense recently expressed a position suggesting that jus in bello applies when a State uses force in exercise of its right of self-defense against a non-State actor. The U.K. Parliament’s Joint Committee on Human Rights summarized his position in its report:

“[T]he Secretary of State went on to assert that where the UK uses lethal force abroad outside of armed conflict, pursuant to the policy we described in Chapter 2 above, it will comply with the Law of War and that compliance will be sufficient to meet any obligations that the UK may have under human rights law. The effect of that assertion is that the UK Government’s policy ends up in the same place as the US policy, despite disavowing the wide American view of the existence of a non-international armed conflict.”

(The Joint Committee on Human Rights expressed a disapproving view of the Secretary of State’s position.)

6. 1962 Commission of Experts

The 2016 Commentaries suggest that a Commission of Experts convened by the ICRC in 1962 identified the intensity of violence as a condition for application of Common Article 3 (paras. 424-25).  However, the Commission’s statement arguably suggests that intensity of violence is not an essential condition but rather one of several factors to consider in the mix. The Commission stated:

“In the Commission’s opinion, the existence of an armed conflict, within the meaning of article 3, cannot be denied if the hostile action, directed against a legal government, is of a collective character and consists of a minimum amount of organization. In this respect and without these circumstances being necessarily cumulative, one should take into account such factors as the length of the conflict, the number and framework of the rebel groups, their installation or action on a part of the territory, the degree of insecurity, the existence of victims, the methods employed by the legal government to re-establish order, etc.” (emphasis added)

In addition, this statement, carefully considered, describes only conditions in which the existence of an armed conflict “cannot be denied.” That is, the Commission’s statement specifies sufficient but not necessary conditions for the application of Common Article 3—and those may be the most obvious conditions (when it “cannot be denied”).

IV. A Puzzle: Law of armed conflict outside of armed conflict?

Some of the sources listed above appear to suggest that the law of armed conflict might apply outside of an established armed conflict. Put another way, the sources appear to be asking not the question of what is the threshold for a NIAC, but what is the threshold for applying the laws of war even “outside of an armed conflict.” The OLC 2010 memo, in describing the ICJ Nuclear Weapons Advisory Opinion, stated: “fundamental law-of-war norms are applicable even where military force might be employed outside the context of an armed conflict, such as when using powerful weapons in an act of national self-defense.” The U.K. Secretary of State for Defense, as described by the Parliamentary committee, said: “[T]he Secretary of State went on to assert that where the UK uses lethal force abroad outside of armed conflict, pursuant to the policy we described in Chapter 2 above, it will comply with the Law of War and that compliance will be sufficient to meet any obligations that the UK may have under human rights law.”

We think these constructions potentially involve category mistakes. It is axiomatic that the laws of war apply (only) to armed conflict (and closely related contexts such as belligerent occupation).  When a State acts outside of armed conflict, the law of armed conflict does not apply as a legal matter. There are potentially ways to interpret the puzzling sources—the OLC Memo and the U.K. position—to be consistent with these axioms. The latter, for example, may reflect a policy choice (or perhaps a perceived international human rights obligation), and not a decision dictated by a legal understandings of international law of war obligations. The reasoning of the OLC Memo may be overdone, because any meaningful level of armed force between two States will constitute an international armed conflict. And use of “powerful weapons” against an organized non-state armed group in self-defense will presumably cross the threshold for intensity of violence for a NIAC upon the first such use.  It may also be consistent with these sources to understand that, at least, the law of armed conflict restraints on the use of force apply to the initial resort to armed force, outside the context of a pre-existing armed conflict.

We are, however, still left to puzzle over these statements on the law, and, in particular, whether otherwise applicable international human rights law is displaced by the law of armed conflict with respect to an initial resort to armed force. We readily admit that such doubts undermine the use of such statements as support one way or the other on this matter. Nevertheless, the remaining list of counterexamples to the Tadić /ICRC approach is formidable. The burden, as we suggest, is on those who want to extend the Tadić approach to other determinations of NIAC. It is doubtful one could meet that burden, given these counterexamples.

The views expressed herein are those of the authors and do not necessarily represent the views of the Department of the Navy, the Department of Defense, or the United States.