Federica Favuzza (Università di Milano)

At the time of writing, the conflict in Ukraine has been raging for days. As Russian troops entered Ukrainian territory from its Northern, Eastern and Southern borders, allegedly soon to be joined by Belarusian troops, and the so-called Donetsk and Luhansk People’s Republics started evacuating some of their residents to Russia and conscripting others, Ukraine mobilised its population in an attempt to push back Russian invasion. Negotiations are currently underway, with Ukraine asking for a ceasefire and the withdrawal of Russian troops, and Russia demanding the recognition of its sovereignty over Crimea and the demilitarisation of Ukraine. Whilst there is little doubt that «active hostilities» within the meaning of international humanitarian law are currently taking place in the country (see: Updated Commentary to Art. 118 of the III Geneva Convention, paras 4452-4460), and despite President Putin originally claiming that Russia’s plans didn’t include occupation, the question of whether Russia is (or will be) occupying parts (or whole) of Ukraine still arises. This question is particularly relevant for at least two reasons.

First, from a purely jus in bello perspective, the existence of a belligerent occupation bears some important consequences on applicable rules of international humanitarian law (IHL). The immediate, most obvious consequence is the applicability of a sub-set of IHL rules that is generally referred to as «occupation law». This is embodied in the Regulations concerning the Laws and Customs of War on Land annexed to the Convention (IV) respecting the Laws and Customs of War on Land (the Hague Regulations), the IV Geneva Convention Relative to the Protection of War Victims of 1949 (GC IV), Additional Protocol I to the Geneva Conventions of 1977 (API), and a few other treaties relating to specific fields (e.g., the Convention for the Protection of Cultural Property in the Event of Armed Conflict of 1954). The rules of occupation law clearly reflect the peculiar nature of belligerent occupation, which «lies midway between war and peace and is characterized by the resumption of civilian life» (Campanelli, p. 654). They are, in general, far more detailed and, in some respects, far more protective than IHL rules otherwise applicable in the context of an international armed conflict. Consider, e.g., the duty of ensuring the essential supplies to the population (Art. 55(1) GC IV and Art. 69(1) API), the rules on internment, including some procedural safeguards (Art. 78 GC IV), those on the administration of justice (Arts 54 and 64 ff. GC IV), and those on private property, including detailed provisions on seizure, requisition, confiscation, and taxes (see esp. Art. 46 ff. of the Hague Regulations).

Furthermore, should the conflict in Eastern Ukraine also qualify as an international armed conflict and/or a belligerent occupation (more on that below), applicable IHL rules would include those on the so-called «grave breaches», i.e., particularly serious violations of  IHL which «give rise to specific obligations of repression for States [parties to the relevant treaties]», as these violations «must be prosecuted … on the basis of the principle of universal jurisdiction» and, «together with other serious violations of IHL, … constitute war crimes» (Sassòli et al.). Suffice it to mention that compelling a protected person to serve in the forces of a hostile Power – as the separatists would be doing, should Russia be indeed found to be an occupying power controlling their actions (see below) – is a grave breach under Art. 147 IV GC (see Kalandarishvili-Mueller).

Last, but not least, another important consequence of determining that whole or parts of Ukraine are under Russian belligerent occupation relates to a specific aspect of the qualification as lawful combatants, i.e., combatants who, if fallen into the power of the enemy (e.g., by capture), are entitled to prisoner of war status, and may not be tried for their participation in the hostilities (see, inter alia, Sassòli et al.; Dinstein, p. 41 ff.). In particular, reading of ordinary Ukrainians resisting the invasion with home-made weapons, the so-called «levée en masse» comes to mind. This expression refers to «[i]nhabitants of a non-occupied territory, who on the approach of the enemy spontaneously take up arms to resist the invading forces, without having had time to form themselves into regular armed units, provided they carry arms openly and respect the laws and customs of war» (Art. 4(A)(6) of the III Geneva Convention (emphasis added)). Thus, Ukrainians fighting the invaders without enlisting could only be considered lawful combatants insofar as they did so «spontaneously to [respond to] an approaching and invading enemy» and until they have had the time to «either be replaced by the regular armed forces of their State, formally integrate into them or form groups which meet the conditions» set forth at Article 4A(2) for members of militias or volunteer corps not forming part of the official armed forces (see Updated Commentary to Art. 4 of the III Geneva Convention, para 1064 ff.). In this respect, it has been argued that, after the first day(s), the «level of involvement on the part of the Ukrainian government would seem to preclude the existence of a levée en masse, by eliminating the ‘spontaneity’ element of a levée» (Crawford). In any event, once a belligerent occupation begins, the «levée en masse» no longer applies.

Second, from a regime interaction perspective, the qualification of the current situation in whole or parts of Ukraine as belligerent occupation could also have some important consequences on the applicability ratione loci of international human rights law and the (likely) future litigation of these events before international courts and human rights treaty-based bodies (see the inter-state application that has already been lodged with the European Court of Human Rights, which has decided to indicate urgent interim measures to Russia). This is particularly true when it comes to the European Convention of Human Rights (ECHR). Indeed, in its 2021 judgment in the case of Georgia v Russia (II), the Grand Chamber made a sharp distinction between the events which had taken place during the active phase of hostilities (from 8 to 12 August 2008) and those having occurred in the subsequent occupation phase (after the ceasefire agreement of 12 August 2008). It recalled that the States parties’ obligation under Article 1 of the ECHR «to secure to everyone within their jurisdiction the rights and freedoms guaranteed by the Convention is … closely linked to the notion of “control”, whether it be “State agent authority and control” over individuals or “effective control” by a State over a territory» (para 136; see also, inter alia, the Al-Skeini case, para 131 ff.). However, somewhat surprisingly and certainly unsatisfactorily, the Grand Chamber held that the events complained of did not fall within Russian jurisdiction, as «the very reality of armed confrontation and fighting between enemy military forces seeking to establish control over an area in a context of chaos not only means that there is no “effective control” over an area …, but also excludes any form of “State agent authority and control” over individuals» (para 137). By contrast, as far as the occupation phase is concerned, the Court unsurprisingly concluded that, due to the «substantial Russian military presence after hostilities had ceased» and the de facto control exercised by Russia on local authorities, the events complained of fell within Russian jurisdiction (paras 165 and 174). Thus, the question of whether whole or parts of Ukraine are under Russian occupation and – should that be the case – since which point in time is extremely important from the perspective of international human rights law as well.

Before considering the Ukrainian situation, it is worth recalling that, pursuant to Art. 42 of the Hague Regulations, a «territory is considered occupied when it is actually placed under the authority of the hostile army», and «the occupation extends only to the territory where such authority has been established and can be exercised». In the light of this provision, as well as of the first sentence of Art. 43 of the Hague Regulations («the authority of the legitimate power having in fact passed into the hands of the occupant …») and Art. 2(2) IV GC («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»), belligerent occupation may be defined as the situation in which foreign troops exercise effective control over the territory of another State without the latter’s consent (see, inter alia, Benvenisti 2009).

In the light of this definition of belligerent occupation, it appears that, as things stand today, Ukrainian strenuous resistance is preventing Russian troops from effectively controlling vast portions of Ukrainian territory. Indeed, whilst Russian troops have entered into Ukrainian territory and are trying to seize control of its main cities, both the army and the population are fighting back, so far preventing them from establishing their authority over the whole country. However, a few considerations are due in relation to (i) some border areas from which the Russian invasion is being launched, (ii) the areas already involved in the 2014 conflict (i.e., Crimea and the so-called Donetsk and Luhansk People’s Republics), and (iii) other areas where Russian troops are present.

First, although occupation is not officially Russia’s goal, according to some news outlets Russian troops are indeed controlling some of the border areas from which they are launching their attacks. The determination of whether these areas are currently under Russian occupation depends on the interpretation of the abovementioned expression ‘effective control’. Indeed, some contend that, in order to conclude that a State is an occupying power, it must actually exercise its authority over a foreign territory (so-called ‘actual control test’) (see the 2003 judgment in the case of Naletilić and Martinović, para 217, in which the International Criminal Tribunal for former Yugoslavia expressly listed the establishment of a temporary administration by the occupier and the issuance and enforcement of directions to the civilian population as fundamental elements of a belligerent occupation). However, it could be argued that endorsing this theory would result in a legal vacuum, as the application of occupation law would ultimately depend on the foreign troops’ willingness to exercise their authority. Instead, occupation law is to be applied whenever foreign troops have succeeded in ousting the legitimate sovereign and are therefore capable of establishing their own authority (so-called ‘potential control test’) (Bothe, p. 39; on this debate, see also, inter alia, Annoni, p. 45 ff.). Thus, it is submitted that a situation of belligerent occupation exists when (i) hostile troops are present within a State’s territory or parts thereof, (ii) the ousted government is unable to exercise its authority over said territory, and (iii) the foreign army is in the position to exercise governmental functions in lieu of the legitimate sovereign (Benvenisti 2009). It follows that, in principle, there is no reason to believe that the abovementioned border areas could not be considered as occupied territories, as «[o]nce an invader has gained control over a part of an invaded territory, the law of occupation applies, even if the movement forward that precedes such control is continuing in other parts of the territory» (Bothe, p. 40). Still, even if these news reports were to be confirmed, Russian occupation over these areas could eventually end up lasting for a very short time: not only could Ukrainian forces succeed in taking back control, but the withdrawal of Russian troops could also be either unilaterally carried out by Russia or agreed upon in ongoing negotiations (although, in the latter case, some doubts could arise as to the validity of any agreement pursuant to Article 52 of the Vienna Convention on the Law of Treaties when one of the contracting parties is using force against the other one and is still present in its territory). Would it still be possible to conclude in favour of the application of occupation law to these areas? The answer should be in the affirmative, as nothing prevents occupation law from applying for a limited window of time insofar as a certain degree of stability is achieved (see Longobardo, p. 35, citing the Supreme Court of Israel’s judgment in the case of Tsemel et al., (quoted in Benvenisti 2012, p. 200) and the Partial Award of the Eritrea-Ethiopia Claims Commission, p. 307).

Second, the qualification of current events is complicated by the fact that parts of Ukrainian territory have already been involved in an armed conflict since 2014, when Crimea was annexed to Russia and an armed conflict broke out in Eastern Ukraine. As far as Crimea is concerned, its continued qualification as an occupied territory is widely supported (see, inter alia, Dinstein, p. 13; Heinsch, p. 352; International Criminal Court, Office of the Prosecutor, Report on Preliminary Examination Activities (2016), paras 155-158; RULAC: Rule of Law in Armed Conflicts). By contrast, the classification of the conflict is Eastern Ukraine is far more controversial, as its qualification as a belligerent occupation depends on the degree of Russia’s control over the so-called Donetsk and Luhansk People’s Republics (on its possible qualification as an international armed conflict, see RULAC: Rule of Law in Armed Conflicts). This is linked to the notion of «occupation by proxy», i.e., the situation in which a State, even without deploying its troops on the ground, acts in the territory of another State through local entities operating on its behalf (Updated Commentary to common Art. 2 to the Geneva Conventions, para 328). When trying to ascertain whether an occupation by proxy exists, one must investigate the relationship between the State and the entities in question and be satisfied that a certain degree of control over the latter’s actions is exercised by the former. Although the threshold for said control is still debated (see Kalandarishvili-Mueller; Updated Commentary to common Art. 2 to the Geneva Conventions, para 331), it could be argued that what suffices is a foreign State’s overall control over local entities which are themselves exercising effective control within the meaning of occupation law (as defined above), with the expression ‘overall control’ referring to the act of not only equipping and financing an entity, but also coordinating or helping it in the general planning of its military activities (with no need to also prove the issuance of instructions for the commission of specific acts contrary to international law) (Tadić case, para 131). As far as the conflict in Eastern Ukraine is concerned, prior to recent events this was widely regarded as a non-international armed conflict between the two separatist Republics and the Ukrainian State (although a few hostile encounters between Russian and Ukrainian forces could have led to conclude that at some point a parallel international armed conflict existed), as Russia’s overall control over the separatists could not be proved (see RULAC: Rule of Law in Armed Conflicts; contra, e.g., Ukraine). Is it reasonable to conclude that, due to recent events, Russia now exercises such a degree of control? Despite some views to this effect (see Kalandarishvili-Mueller), it might be a stretch to argue so: at present, neither the separatists’ call for a general mobilisation right before Russian invasion, Russia’s availability to provide refuge to their residents, nor the deployment of Russian so-called peace-keepers (who may have just used the separatists’ territory to carry out their invasion of the rest of Ukraine),  prove such a high degree of involvement, however likely that might be (especially considering the precedents of Transdniestria, Abkhazia and South Ossetia). This opinion is shared, e.g., by Sassòli, who notes that, «[w]hile evidence suggests that Russia is training and equipping these armed groups and providing them with weapons, information at our disposal does not allow us to conclude with a degree of certainty that Russia exercises overall control over them by coordinating or helping in the general planning of their military operations».

A separate, yet intertwined question is that of the recent recognition of so-called Donetsk and Luhansk People’s Republics as independent States by Russia. Apart from the question of the lawfulness of said recognition under international law, the matter is of relevance for the purposes of the applicability of occupation law as well. Indeed, if Russian overall control over these entities were to be proved, their consent could in principle lead to qualify the situation as a pacific occupation, resulting in the inapplicability of occupation law. Indeed, when a military occupation is consented to, then it is not hostile and is not regulated by IHL (see, among others, Benvenisti 2009; Roberts, p. 276). The same issue arose, at first, in the case of Crimea, as Russia relied, inter alia, on the ousted President Yanukovych’s consent to deny being an occupying power. However, just like in that case consent was not valid since it did not come from an organ competent to speak on behalf of the State, in the present case – considering that these self-proclaimed republics cannot be said to be States under international law – they cannot consent to any occupation of the territories concerned, which they merely control as insurgents and which continue to be subject to Ukraine’s sovereignty.

Finally, the question should also be addressed of whether occupation law applies not only to the abovementioned border areas (however long their occupation may last) and the Crimean Peninsula, but also other areas of the country where Russian troops are present. The answer depends on the stance to be taken in the decades-long debate of whether occupation law should also apply during the invasion phase. Indeed, «the transition between the invasion and occupation phases is particularly difficult to identify with exactness» (Tristano, p. 135). This and the need to fill the protection gap otherwise left by IHL for affected populations are the main reasons why some contend that occupation law already applies during the invasion phase. In particular, according to the so-called ‘Pictet theory’, «there is no intermediate period between what might be termed the invasion phase and the inauguration of a stable regime of occupation», so that «even a patrol which penetrates into enemy territory without any intention of staying there must respect the Conventions in its dealings with the civilians it meets» (see also Sassòli 2012). However, this theory is not widely agreed upon. Relying on the abovementioned provisions of the Hague Regulations, it seems reasonable to argue instead that occupation law begins to apply once the occupying State has ousted the legitimate sovereign and is in a position to exercise its own authority over the territory in question, (see, inter alia, Bothe; Naletilić and Martinović, para 217). This leads to exclude the application of occupation law to those areas within Ukraine where Russian troops are present without exercising their control.

In the final analysis, it seems reasonable to conclude that, beside the Crimean Peninsula, only some border areas are currently under Russian occupation, although said occupation may soon either expand to other areas of the country or end. As for the territories currently controlled by the so-called Donetsk and Luhansk People’s Republics, at this point it is not possible to determine that any significant change has occurred in their relationship with Russia and that the latter exercises such overall control as to make it an occupying power by proxy.