Ukraine Symposium – Classification of the Conflict(s)

The threshold questions in any international humanitarian law (IHL) analysis are whether an armed conflict is underway as a matter of law and, if so, what type. They are determinative questions because the existence of an armed conflict is a condition precedent to IHL’s application. Should one exist, the aspects of that law that apply depend on whether the conflict is “international” or “non-international” in character.

The differences between the two forms of conflict are significant. A number of treaties govern both international and non-international armed conflict, although, with the notable exception of the Second Protocol to the 1954 Hague Cultural Property Convention, they deal primarily with weapons (e.g., 1972 Biological Weapons Convention, 1993 Chemical Weapons Convention, 1997 Anti-Personnel Land Mines Convention, 2001 Amendment to the Conventional Weapons Convention, 2008 Cluster Munitions Convention).

But most IHL treaty law is specific to one or the other form of conflict. For instance, during an international armed conflict, the Regulations annexed to the 1907 Hague IV Conventions, the four 1949 Geneva Conventions, and, for Parties, Additional Protocol I to those Conventions apply. During a non-international armed conflict, Common Article 3 to the 1949 Geneva Conventions, which contains only basic provisions, and the relatively short Additional Protocol II provide the bulk of applicable treaty law. The latter does so only for Parties to the instrument and only in certain types of non-international armed conflicts (see below). Additionally, the body of customary international law applicable in international armed conflict is denser than that governing non-international armed conflict. Finally, and of particular significance for those engaging in hostilities, it is only during an international armed conflict that the notions of combatant and prisoner-of-war status exist.

In this post, I assess the nature of the conflict in Ukraine from its inception in 2014 through the present. Classification of this conflict, or more accurately, these conflicts, is complex, for the situation in Ukraine has at times been “mixed,” either because international and non-international conflicts were ongoing contemporaneously (“horizontally” mixed) or occurring sequentially (“vertically” mixed) (on such situations, see Dinstein at 40-42). Moreover, the situation’s facts have often been challenging to evaluate because of Russia’s efforts to mask its involvement, the claims of separatist groups to independence, and a lack of clarity regarding the relationship between Russia and various organized armed groups fighting the Ukrainian government. Despite these obstacles, I will attempt to disentangle the facts to identify the type of armed conflicts that took, and are still taking, place.

The Bifurcated Typology of Classification

 The contemporary typology of armed conflict emerged following the Second World War. Before then, the Parties to the 1907 Hague Convention III relative to the Opening of Hostilities had agreed that “hostilities between themselves must not commence without previous and explicit warning, in the form of either a declaration of war, giving reasons, or of an ultimatum with conditional declaration of war” (art. 1). Concerned that the application of the laws of war not be held hostage to political decisions as to whether to declare war, the 1949 Geneva Conventions adopted a fact-based approach to the existence of an “armed conflict” (a term adopted in lieu of “war”), as the condition for application of those instruments. Additionally, the Conventions, for the first time, addressed internal conflict. The decision to do so was partly motivated by the Spanish Civil War, which had been as violent and internationally destabilizing as many State-on-State wars.

To address these concerns, the Geneva Conventions established a bifurcated typology of war that distinguished between “international” and internal (“non-international”) armed conflict. Common Article 2 to the four Geneva Conventions set forth the threshold at which the former occurred. It provides that “the present Convention shall apply to all cases of declared war or of any other armed conflict which may arise between two or more of the High Contracting parties, even if the state of war is not recognized by one of them.” The article goes on to note, “The Convention shall also apply to all cases of partial or total occupation of the territory of a High Contracting Party, even if the said occupation meets with no armed resistance.” Common Article 3, by contrast, dealt with “armed conflict not of an international character occurring in the territory of one of the High Contracting Parties,” and laid out a small number of rules to govern such internal conflicts.

By this bifurcation, the specific rules that apply to a conflict depend on who the parties are. International armed conflict involves hostilities between States, while non-international conflict occurs when violence of a certain intensity takes place between a State and an organized armed group or between organized armed groups. Today, the two articles are universally acknowledged as reflecting customary law, although some difference of opinion exists regarding their precise scope (for instance, over the geographical scope of non-international armed conflict, see here).

In the following discussion, it is essential to remember that hostilities in one area of a country that qualify as an international or a non-international armed conflict extend that conflict throughout the country. Thus, the IHL rules apply everywhere in the belligerent States in the case of an international armed conflict and throughout the State involved during a non-international armed conflict. This is so irrespective of whether there are ongoing hostilities in a location. For instance, once an international armed conflict was underway between Russia and Ukraine due to Russia’s invasion of Crimea (see below), there was no need for the situation in the Donbas region to qualify as one before applying the relevant international armed conflict IHL rules to Russian and Ukrainian forces there. Nevertheless, in the following discussion, I will tease out the multiple grounds for conflict characterization in Ukraine to illustrate how they apply.

International Armed Conflict

International armed conflict exists in three circumstances: 1) when there are hostilities between the armed forces or other organs of States; 2) during belligerent occupation of one State by another; and 3) when a State is in “control” of an organized armed group fighting another State. A fourth type of international armed conflict is limited to Parties to Additional Protocol I and involves groups fighting for self-determination.

The Law: In oft-cited text, the International Committee of the Red Cross (ICRC) 1958 Geneva Convention IV Commentary to Common Article 2 explains that “Any difference arising between two States and leading to the intervention of members of the armed forces is an armed conflict within the meaning of Article 2, even if one of the Parties denies the existence of a state of war. It makes no difference how long the conflict lasts, or how much slaughter takes place” (see also International Criminal Tribunal for the former Yugoslavia, Delalić, ¶ 208).  The updated  2015 ICRC Geneva Convention I Commentary to the article emphasizes that “Even minor skirmishes between the armed forces, be they land, air or naval forces, would spark an international armed conflict and lead to the applicability of humanitarian law.” While some commentators suggest that isolated or sporadic uses of force do not suffice, all agree that the intensity and duration threshold is quite low, and that the classification assessment is factual.

An international armed conflict can also be triggered (or continued) by belligerent occupation. This is so even if the occupation is unopposed, a caveat that derives in part from the unopposed occupation of Denmark by German forces during the Second World War. As used in Common Article 2, “occupation” has the same meaning as the term’s usage in Article 42 of the 1907 Hague Regulations: “Territory is considered occupied when it is actually placed under the authority of the hostile army. The occupation extends only to the territory where such authority has been established and can be exercised.” The ICRC’s 2015 Geneva I Commentary explains that this status requires the satisfaction of three constitutive elements (¶ 300):

• the armed forces of a State are physically present in a foreign territory without the consent of the effective local government in place at the time of the invasion;
• the effective local government in place at the time of the invasion has been or can be rendered substantially or completely incapable of exerting its powers by virtue of the foreign forces’ unconsented-to presence;
• the foreign forces are in a position to exercise authority over the territory concerned in lieu of the local government

A third basis for characterizing a conflict as international is “overall control” by one State of an organized armed group fighting another State. In Tadić, the Appeals Chamber of the International Criminal Tribunal for the former Yugoslavia (ICTY) described overall control as “going beyond the mere financing and equipping of such forces and involving also participation in the planning and supervision of military operations” (¶ 145). And in Lubanga, the International Criminal Court explained that it involved “a role in organising, coordinating, or planning the military actions of the military group.” (¶ 211). Thus, while the State need not direct individual operations to have overall control of an organized armed group, it must exercise a degree of de facto decision-making authority. Once it does, the existing non-international armed conflict becomes international; it has been internationalized.

Finally, Additional Protocol I controversially extends to “armed conflicts in which peoples are fighting against colonial domination and alien occupation and against racist regimes in the exercise of their right of self-determination” (art. 1(4)). The provision led numerous States (in part), including the United States, to refuse to become a Party to the instrument (2022 Law of War Documentary Supplement at 249). Most commentators agree that it does not reflect customary international law. Nevertheless, as Ukraine and Russia are Party to the instrument, they are bound by the provision.

International Armed Conflict Between Russia and Ukraine

In a previous post in this series, I discussed the background to the outbreak of hostilities in 2014. The critical moment regarding the classification of the situation came when the “Euromaidan” protests forced President Victor Yanukovych to flee to Russia in February 2014. Soon thereafter, Russian soldiers without distinctive uniforms or other insignia identifying them as such (the so-called “little green men”) entered Crimea and seized strategic locations, including Crimea’s parliament (Verkhova Rada). Although Russia initially denied that its soldiers were involved and branded them as volunteers, President Putin later acknowledged that its troops “stood behind Crimea’s self-defence forces” and that the little green men were Russian military personnel. The involvement of Russian forces in the military operations clearly triggered an international armed conflict between Ukraine and Russia.

In March, pro-Russian elements in Crimea issued the Declaration of Independence of the Autonomous Republic of Crimea and Sevastopol. That month, nearly 97% of the population supposedly voted for annexation, which Russia promptly approved. The move was widely, and accurately, condemned as unlawful (e.g., U.N., E.U.). The fact that Russia stationed troops in Crimea and maintains the presence today, combined with the fact that it has governed the territory since then, makes it unquestionable that Russia continues to occupy Crimea as a matter of law. Therefore, on that basis alone, the two countries remained in a state of international armed conflict following Russia’s initial operations. As noted above, that conflict extended throughout Ukrainian and Russian territory.

Classifying the hostilities in the Donbas region of eastern Ukraine is more complicated. Populated primarily by ethnic Russians, anti-Euromaiden demonstrations descended into open hostilities between armed separatist groups and government forces. In April 2014, Luhansk and Donetsk declared independence and established “People’s Republics.” As with Crimea, the declarations were of no legal effect. The conflict soon escalated, with Russia shifting from providing materiel and volunteers to direct military involvement.

Putin claimed for some time that Russian forces were not supporting the armed forces of the two rebel governments. But by December 2015, he admitted they were present in the area, although he still insisted they were not regular soldiers. The facts suggest otherwise. For example, the State Department estimated that by late 2015, 400-500 Russian soldiers had been killed in the fighting in the Donbas. Moreover, Ukrainian forces captured Russian soldiers, who were then controversially tried on terrorism charges. And large-scale cross-border shelling took place as well. In my estimation, from mid-2014 on, Russian and Ukrainian forces were engaged in hostilities against each other in the region that provide a further basis for characterizing the two States as involved in an international armed conflict (accord, 2016 Prosecutor ICC Preliminary Report, ¶ 169).

Another possible basis for characterizing the hostilities in the east as international is Russia’s control over separatist forces in eastern Ukraine. Before 2022, Russian troops tended to support separatist units and provide training and arms. Yet, as noted, financing, training, and equipping an organized armed group does not rise to the level of overall control. And the mere fact of some Russian military support to the separatist forces does not necessarily amount to overall control; the State in question must exert the requisite degree of control over the organized armed groups. Of course, the fighting between Russian and Ukrainian forces itself qualifies the exchanges as an international armed conflict between the two States, but it does so based on hostilities, not overall control. Over time, however, Russian forces exerted ever-increasing control over separatist forces. Therefore, by early 2022, and perhaps somewhat earlier, it is reasonable to assert that the requisite level of control had been achieved

In that year, all doubt as to internationalization would be erased. On 21 February, Russia recognized the Statehood of Donetsk and Luhansk and ordered troops (Putin called them “peacekeepers”) into the area. Once renewed fighting was underway on February 24, Russia quickly integrated separatist forces into its operations. For example, Russia’s 8^th Combined Arms Army commanded the separatist units in Donetsk and Luhansk. And separatist troops did most of the fighting in the battle for Mariupol. Thus, early in the second phase of the conflict, the ongoing non-international armed conflict was internationalized (assuming it had not been internationalized already) by virtue of Russia’s overall control of separatist operations (see also the thorough RULAC analysis).

Note that on 17 November 2022, the Hague District Court issued a verdict in the case of four defendants accused of involvement in the MH17 shootdown over Ukraine on 17 July 2014. One of the issues the Court dealt with was combatant immunity. As combatant immunity only exists during an international armed conflict, it had to make a finding on the characterization of the conflict in eastern Ukraine, specifically whether the armed conflict had been internationalized based on Russia’s overall control of the separatists.

According to an account of the decision (which has yet to be translated), the Court surveyed various evidence to find “that there was an ‘abundance of evidence’ that the Russian Federation coordinated the DPR’s military activities and in fact gave direct instructions to its leadership.” Thus, “from mid-May 2014 until at least the shooting down of flight MH17, the Russian Federation exercised overall control over the DPR.” The Court went on to find that the defendants were not combatants and therefore did not enjoy combatant immunity.

Which of these characterizations is the sounder one depends on the facts, many of which are likely not available in open sources. If the conflict was internationalized by 2015, the more developed IHL of international armed conflict would apply between Ukrainian forces and the separatist units, and Additional Protocol II (see below) would not.

A further basis for characterizing the conflict as international is the Russian occupation of large swaths of eastern Ukraine. It might be questioned whether Russia occupied eastern Ukraine by proxy before 2022 (see discussion by Heinsch). But as Yoram Dinstein has noted, “there is a double requirement of effective control relating to auxiliary forces: the militias must be in effective control of the territory, and the occupying power has to be in effective control of the militias.” He goes on to explain, “the question is whether the militias can be regarded as the de facto organs of the occupying power” (at 50).

Had Russia been in effective control of the separatists (a threshold higher than overall control), it would have been in belligerent occupation of the area that the separatists controlled, thereby providing yet another ground for characterizing the conflict as international. However, in my view, that degree of control does not appear to have been exercised until, perhaps, sometime in 2022. Nevertheless, once Russia annexed the four regions of Donetsk, Luhansk, Kherson, and Zaporizhzhia in September 2022, any doubt that its forces were in belligerent occupation of territory their forces and the separatists controlled vanished.

Finally, because Ukraine is a Party to Additional Protocol I, an additional basis for the existence of an international armed conflict between it and the separatists that must be considered is self-determination as envisioned in Article 1(4) of that instrument. However, its applicability can quickly be dismissed (on the subject, see the discussion by Chris Borgen).

As is clear from the ICRC Commentary to the article (¶¶ 81-85), the reference to self-determination in Article 1(4) has the same meaning as in the 1970 U.N. General Assembly Declaration on Friendly Relations. The Declaration states that the principle of self-determination  is not to be understood “as authorizing or encouraging any action which dismembers or impairs, totally or in part, the territorial integrity or political unity of sovereign and independent States conducting themselves in compliance with the principle of equal rights and self-determination of peoples . . . and thus possessed of a government representing the whole people belonging to the territory without distinction as to race, creed or colour.” Since the Ukrainian government is independent, represents the whole people, and upholds the principle of equality, the provision does not apply to the efforts of the various regions to break away from Ukraine.

Non-international Armed Conflict

The Law: As noted, Common Article 3 defines non-international armed conflicts in the negative as those that are “not of an international character.” The ICTY further developed the notion in a manner that is generally viewed as reflecting customary international law. Most notably, in Tadić, the Tribunal described such conflicts as “protracted armed violence between governmental authorities and organized armed groups or between such groups within a State” (¶ 70). Other international tribunals have adopted the same definition (e.g., International Criminal Tribunal for Rwanda, Akayesu, ¶ 619; International Criminal Court, Bemba, ¶ 229), and it appears in the Statute of the International Criminal Court (art. 8(2)(f); see also 1957 ICRC Commentary to Geneva Convention IV, at 45-46)). Accordingly, two essential criteria apply for all non-international armed conflicts—participation by an organized armed group and a particular level of intensity.

As to the first requirement, the ICTY noted in Limaj that “some degree of organisation by the parties will suffice to establish the existence of an armed conflict. This degree need not be the same as that required for establishing the responsibility of superiors for the acts of their subordinates within the organization, as no determination of individual criminal responsibility is intended under this provision of the Statute” (¶ 89).

And with respect to intensity, it is generally agreed that riots, civil disturbances, or isolated and sporadic acts of violence do not suffice. This conclusion derives from the exclusion of such violence in Article 1(2) of Additional Protocol II (see also, e.g., ICTR, Akayesu, ¶¶ 619-620). Beyond that, no bright line test exists for the requisite level of violence. ICTY decisions have cited such factors as “the number, duration and intensity of individual confrontations; the type of weapons and other military equipment used; the number and calibre of munitions fired; the number of persons and type of forces partaking in the fighting; the number of casualties; the extent of material destruction; and the number of civilians fleeing combat zones” (Haradinaj, ¶ 49).

Additional Protocol II set a higher threshold for applicability during a non-international armed conflict than Common Article 3. By Article 1(1), the Protocol applies “to all armed conflicts which are not covered by Article 1 of the [Additional; Protocol I] and which take place in the territory of a High Contracting Party between its armed forces and dissident armed forces or other organized armed groups which, under responsible command, exercise such control over a part of its territory as to enable them to carry out sustained and concerted military operations and to implement this Protocol.” The requirement of control over territory and the limitation to conflicts with States differentiate Additional Protocol II non-international conflicts from those falling within Common Article 3’s reach. Because Russia and Ukraine are Parties to Additional Protocol II, the treaty applies to the extent these further requirements are met.

Non-international Armed Conflict between Ukraine and Separatist Groups

It does not appear that there was sufficient fighting between organized armed groups and Ukrainian forces in Crimea in 2014 to initiate a non-international armed conflict. On the contrary, as discussed above, the civil disturbances were quickly supplanted by the Russian invasion of the area. To the extent separatist organized armed groups were active, they were within days under the overall control of Russia. More to the point, the Russian operations standing alone triggered an international armed conflict.

The situation in the east differed. As noted above, the anti-Euromaidan protests rapidly turned into armed confrontations with Ukraine’s armed forces. The separatists seized control of strategic locations and declared the independence, contrary to international law, of the Donetsk and Luhansk People’s Republics. They formed proper military units and took control of large areas in the Donbas. By late April, the Ukrainian President announced that most control over the area had been lost, and the counter-terrorist operations by the Ukrainian security services were replaced by a “joint forces operation.”

Plainly, the separatist forces were organized at a level well above the threshold required for qualification as a non-international armed conflict. At the same time, the military operations were sufficiently intense, as evidenced by the inability of the Ukrainian armed forces to regain control of the territory in question. As a result, the situation in the Donbas qualified as a horizontal conflict in which Ukraine and Russia were fighting an international armed conflict while Ukraine was engaged in a non-international armed conflict with separatist forces at the same time.

Note that during this period, the parties agreed to two formal ceasefires. In September 2014, they approved the Minsk I ceasefire, but it was quickly violated. Then, in February 2015,  Ukraine, Russia, France, Germany, and the separatist groups negotiated a new ceasefire agreement, Minsk II. However, the parties regularly disagreed over its execution, and there were frequent exchanges of fire, often followed by hasty ceasefires. Finally, the Russian operations that commenced in February 2022 terminated the ceasefires once and for all.

Although the fighting in the area often dropped below the requisite level of intensity required for a non-international armed conflict during the various ceasefires, it must be remembered that ceasefires are only temporary cessations of hostilities. Indeed, there were thousands of violations of its terms (see OSCE monitoring reports). Therefore, in my estimation, the non-international armed conflict continued unabated in the same way that a non-international armed conflict continues during temporary lulls in the fighting.

It might be questioned whether there were different non-international armed conflicts underway against the two central separatist forces or just one against them all. In September, the forces of the self-proclaimed People’s Republics formed the United Armed Forces of Novorossiya, with Donetsk’s units comprising the 1^st Army Corps and Luhansk’s making up the 2^nd Army Corps.  However, the effort to create a unified structure was abandoned in less than a year due to in-fighting. As a result, the conflict between Ukraine and the forces of the two armies are distinct non-international armed conflicts assessed separately against the organization and intensity criteria.

Finally, in both cases, the situations qualified as Additional Protocol II non-international armed conflicts. Separatist units controlled significant territory, could impose discipline through a hierarchical command structure, and conducted sustained and concerted military operations. Further, the Donetsk and Luhansk People’s Republics had a judicial system capable of enforcing IHL. As a result, Additional Protocol II governed separatist and Russian actions related to the conflict in addition to applicable customary international law and Common Article 3.

As noted earlier, the non-international armed conflicts with the separatist groups ended once Russia exerted overall control of their operations, and the conflict was internationalized. If the Dutch Court is correct in its assessment that Russia exercised “overall control” as early as July 2017 when MH17 was downed, the non-international armed conflict with the separatists was internationalized by then. If not, internationalization came much later.

Concluding Thoughts

As noted at the outset of this post, conflicts can be of mixed character. Since 2014, there has been an ongoing international armed conflict between Russia and Ukraine throughout the territory of those countries based on the existence of hostilities and Russia’s ongoing belligerent occupation of Ukrainian territory. At the same time, there were non-international armed conflicts between Ukraine and separatist groups in Luhansk and Donetsk. The situation was one of horizontally mixed armed conflicts. Consequently, different IHL rules applied between Russia and Ukraine on the one hand and Ukraine and the separatists on the other.

At some point, but certainly, no later than early 2022, the two non-international armed conflicts in the Donbas were internationalized due to Russia’s overall control of the separatist forces. The result of the vertically mixed conflicts is that today there is but one armed conflict in Ukraine, an international armed conflict between Ukraine and Russia and its proxies. All forces are now subject to the IHL rules applicable in such conflicts.​

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Michael N. Schmitt is the G. Norman Lieber Distinguished Scholar at the United States Military Academy at West Point. He is also Professor of Public International Law at the University of Reading; Professor Emeritus and Charles H. Stockton Distinguished Scholar-in-Residence at the United States Naval War College; and Strauss Center Distinguished Scholar and Visiting Professor of Law at the University of Texas.

Photo credit: Ministry of Defense of Ukraine