In the early morning of July 30, 2023, two remotely controlled aircraft (drones) crashed into office buildings in a business district of Moscow. It was the fifth occasion that such aircraft had entered the Russian capital's airspace since May 3 of that year, when two drones were shot down over the Kremlin.Footnote 1 Following that first drone incursion, Ukraine's president, Volodymyr Zelenskyy denied responsibility: “We don't attack Putin, or Moscow, we fight on our territory and defend our towns and cities.”Footnote 2 Indeed, since the Russian invasion of February 2022, Ukrainian self-defense had been pursued largely as a matter of deoccupying territory in the country's east and south. By the end of May 2023, however, it was becoming clearer that the military effort to defend against Russian aggression was expanding its territorial scope. Ukraine's capital, Kyiv, had recently come under attack by Russian missiles and Iranian-made “kamikaze drones.”Footnote 3 The latter are designed and preprogrammed for one-way flight toward targets and for explosive self-destruction.Footnote 4 Ukrainian general Kyrylo Budanov responded publicly to this attack on Kyiv, warning that “those who tried to intimidate us . . . will regret it very soon.”Footnote 5 Two days later, drones began striking buildings in Moscow, and Russia blamed Ukraine.Footnote 6
The Ukrainian government did not claim responsibility for these strikes inside Russia, but President Zelenskyy responded differently to the drone attacks of July 30, 2023, in Moscow. He implicitly endorsed them as a legitimate action in the context of an unjust war against his country. “Gradually,” the president warned, “the war is returning to the territory of Russia—to its symbolic centres and military bases, and this is an inevitable, natural and absolutely fair process.”Footnote 7 The purpose of this essay is to assess this claim, with the focus on Ukraine's use of drone technology to strike targets inside Russia. The “returning” of war to Russian territory in this way is, of course, neither “inevitable” nor “natural.” Warfare is driven by human decisions, and attacks against Russia do not launch themselves. Thus, the element of Zelenskyy's claim that most warrants assessment is the issue of what wartime actions are “fair” in the sense of being morally justified.
At the time of writing, drone technology is Ukraine's only means of striking distant targets located deep inside Russia. This is because its other weapons, including weapons supplied to Ukraine by its international supporters, are usable only at shorter ranges.Footnote 8 It is currently uncertain whether the Kyiv government has been the author of all drone attacks inside Russia. Some of these might instead have been organized independently by anti-Putin or pro-Ukrainian groups.Footnote 9 For present purposes, though, it is reasonable to proceed on the assumption that wartime attacks against Russia are elements of the Ukrainian government's war effort. The ethical question that then needs to be addressed is whether it would be right for Ukraine to attack Russia's “symbolic centres and military bases.”Footnote 10
Given the Russian invasion into Ukrainian territory, Ukraine clearly has a just cause to wage a war of self-defense. However, its violent efforts to achieve that cause remain subject to moral limits. Among those limits is the jus in bello requirement of discrimination between combatants (who may be targeted) and civilians (who may not). Ukrainian drone-based attacks against Russian “military bases” would likely be discriminate, in the sense of being intended to directly neutralize the enemy's capacity to use force. By contrast, Ukraine would not be justified in intentionally attacking what Zelenskyy referred to as Russia's “symbolic centres,” assuming that these are nonmilitary targets. Such action would be wrong for at least two reasons. First, Russian civilians are not morally liable to attack. This nonliability is not diminished by the injustice of Russia's invasion or by any in bello wrongs committed by the Russian military. Second, attacking Russian population centers with drones would arguably achieve little or no self-defensive benefit for Ukraine. In which case, the benefit of indiscriminate attacks could then be outweighed morally by the risks of potential escalation of the Russo-Ukrainian war and jeopardization of Ukraine's moral authority in this conflict.
Ukrainian Drone Attacks inside Russia
The expansion of war into Russian territory has, for the most part, involved the use of drone technology to strike targets. These long-distance air strikes have contrasted with what has otherwise been a slow-moving war of attrition since February 2022—a war characterized mainly by large deployments of ground troops and the mutual use of artillery to bombard enemy positions. Drone attacks against Russian military assets, widely suspected of being launched by Ukraine, have reportedly been going on since at least August 2022.Footnote 11 The targets have included naval bases in Russian-occupied Crimea and air bases located hundreds of miles inside Russian territory.Footnote 12 During the first eight months of 2023, local media reported more than 190 such attacks in Russia or Crimea.Footnote 13
Rarely has Kyiv officially acknowledged launching an attack, such as it did after a large-scale drone attack (spanning six regions of Russia) at the end of August 2023.Footnote 14 One likely reason for this is that Ukraine's international supporters (including the European Union, the United Kingdom, and the United States) have been concerned to avoid provoking Russia into escalating the war. That concern has motivated persistent refusals by those supporters to supply Ukraine with weapons capable of reaching targets deep inside Russia.Footnote 15 In such circumstances, only “homegrown” drone technology has afforded Ukraine the ability to launch long-range attacks.Footnote 16 Conveniently, though, attributing the use of drones to a specific user can often be difficult. This is partly because, in a drone-based air strike, there is no pilot aboard the aircraft who can be downed, captured, and questioned about their mission. Ukraine has thus been able to strike its enemy at long range in a relatively discreet fashion that avoids the appearance of too blatantly courting the conflict escalation that Ukraine's supporters fear.
In addition to striking Russian military targets, Ukrainian drones have sometimes struck populations centers. Such attacks are more significant from an ethical perspective. During the weeks following Zelenskyy's warning of July 30, 2023, that war was “returning to the territory of Russia,”Footnote 17 the city of Moscow repeatedly came under attack. For example, one drone was filmed exploding in a residential area where a rowing competition was taking place,Footnote 18 and another hit a building in Moscow's financial district.Footnote 19 Later, five people were reportedly injured when a drone struck a railway station in Russia's Kursk region, and three people were killed after a village near the city of Belgorod was attacked.Footnote 20 The latter appears to have been the war's first instance of civilian deaths caused by drone strikes inside Russia. Then, at the end of December 2023, Russian missiles and drones struck multiple Ukrainian cities, killing thirty-nine people. In response, Belgorod was targeted again, this time with a large-scale attack by Ukraine in which more than seventy drones were reportedly launched and twenty people killed.Footnote 21 At a meeting of the United Nations Security Council, convened urgently to discuss the Belgorod attack, the Russian envoy to the UN accused Ukraine of carrying out a “deliberate, indiscriminate attack against a civilian target.”Footnote 22
At the time of writing, it is too early to tell whether Kyiv intended the deaths of civilians on this or any other occasion of drone use. On the one hand, it has been suggested by anonymous Ukrainian officials that “only military infrastructure” inside Belgorod had been targeted.Footnote 23 On the other hand, a statement by Ukraine's president issued immediately prior to that attack indicated a bellicose antipathy toward Russians in general: “We will continue to . . . work towards pushing the war back to these human scum where it came from—home to Russia.”Footnote 24 For now, the truth about intentions and events remains elusive. However, it is still possible and important to consider reasons why the indiscriminate use of drones by Ukraine would be morally wrong.
Russian Civilians’ Nonliability to Attack
As a matter of just war theory, it is well established that civilians cannot be intentionally targeted because they are “innocent,” in the sense of being harmless.Footnote 25 Unlike enemy combatants, civilians lack the capacity to injure or kill. Thus, they present no military threat to be violently neutralized. This basic idea is equally applicable to civilians on both sides of a war, and the belligerents bear an equal duty to adhere to the in bello principle of discrimination. The Russo-Ukrainian war is no exception, and Russia's illegal and unjust actions do not diminish Ukraine's responsibility to avoid harming (Russian) civilians. Since the February 2022 invasion, Russia has appeared to have deliberately targeted the civilian residents of Ukrainian cities on many occasions.Footnote 26 However, for the simple reason that two wrongs do not make a right, Ukraine is not permitted (morally or legally) to retaliate against Russia by launching the same kind of attacks.Footnote 27
Also, Ukraine's in bello responsibility to use force discriminately is unaffected by the ad bellum injustice of Russia's initial invasion and continued pursuit of an unjust cause. When the Security Council met on December 30, 2023, in response to the drone attack on Belgorod, there was a suggestion that Ukraine was not ultimately responsible for Russian civilian deaths. The British envoy to the UN, Thomas Phipps, stated: “If Russia wants someone to blame for the deaths of Russians in this war, it should start with President Putin.”Footnote 28 It is a plausible counterfactual that no Russian civilians would have been killed by Ukrainian drones in 2023 if Russia had not wrongfully invaded Ukraine in 2022. However, the problem with Phipps's claim is its implication that jus in bello ought to be subordinated to jus ad bellum.
There are good reasons to keep these sets of just war principles separate. Otherwise, for example, the attitude might emerge that when a country's own cause for war is more just (jus ad bellum), it is therefore entitled to be less restrained (jus in bello) while fighting to achieve it. Such an attitude is dangerous to civilians. An extreme case of subordinating jus in bello occurred during the American Civil War. Before attacking and burning the Confederate city of Atlanta in 1864, the Union general William T. Sherman expressed the view that the “hellishness” of war is entirely attributable to those that begin it. Accordingly, in Michael Walzer's assessment, Sherman assigned no blame to Union soldiers for the death and destruction they caused.Footnote 29 Rather, this general regarded these harms as the price to be paid by a people (civilians included) who had unjustly rebelled.
Where wars of rebellion or aggression are ad bellum wrongs, it is right to fight back. But even those that resist an enemy—justly and violently—are at least partly responsible for the harm their resistance generates. To focus excessively on an ad bellum injustice (such as Russia's 2022 invasion) is to risk judging war “only at its outermost boundaries” and having too little regard for human suffering within war.Footnote 30 If Ukraine were to attack Russian civilians deliberately (using drones that can reach distant cities), it would not be a good justification to insist that Russia (as the original aggressor) was to blame for any casualties. Such an attack would be morally wrong, and Ukraine's status as a victim of aggression would make no difference to that.
The Injustice of “Morale Bombing” Russia
Alternatively, it might be argued that Russian civilians may be attacked, but for a reason unrelated to the capacity to cause physical harm. Perhaps, as an intended consequence of indiscriminate Ukrainian attacks, a demoralized civilian population could somehow compel President Putin to end the war and withdraw Russian forces from Ukraine. Such an approach could be described as “morale bombing,”Footnote 31 and drones that can reach “enemy” cities could be considered well suited to the task. Reportedly, anonymous Ukrainian officials have sometimes claimed that although drone attacks against Russia generate too little damage to have a major military impact, they can still inflict “psychological harm.”Footnote 32 In turn, according to this view, such harm could eventually undermine public confidence in Putin's ability to protect his own people.Footnote 33 Consistent with President Zelenskyy's vision of “returning” war to Russia,Footnote 34 the idea seems to be that drone strikes can usefully force Russian city dwellers, who would otherwise remain complacent, to desire and achieve the war's termination. Although it remains unclear whether the Ukrainian government truly intends the use of drones to undermine civilian morale, it is nevertheless worth highlighting some reasons why this would be unjust.
The pursuit of demoralization by intentionally killing civilians is wrong because it treats human life as merely a means to an end,Footnote 35 notwithstanding the moral importance of achieving that end. Moreover, killing that is regarded as being instrumentally valuable is morally cheapened by its uncertain effectiveness. Any self-defensive effect to be derived from morale bombing could only be indirect, as it depends upon the willingness of a bombed people's leader to decide against continuing the war.Footnote 36 This stands in contrast to the tendency of discriminate warfare to be directly effective. Ukraine's use of drones against military bases in Russia, for example, has the potential to diminish the enemy's material capacity to use force. Drone attacks of this kind are also militarily beneficial if, by forcing the rearward reassignment of Russian air defense assets, Russian positions on the front line (in southern and eastern Ukraine) are made more vulnerable to Ukrainian attacks. In the case of any civilian targeting attacks that Ukraine might launch in the cause of self-defense, it seems highly unlikely that these would be effective. Since the invasion of 2022, even small acts of civil protest inside Russia have been severely punished,Footnote 37 and in that year alone more than twenty thousand people were imprisoned for publicly opposing the war.Footnote 38 Given such repressive conditions, it is arguably unreasonable to expect that morale bombing would induce a mass movement to stop Putin's war, even if Russian cities were struck by weapons more destructive than kamikaze drones.
A worse possibility, compounding the injustice, is that attacking Russian civilians might be counterproductive. In this regard, the British policy of bombing German cities during World War II provides an important lesson. The policy (pursued from 1942 to 1945) was motivated by an intention to destroy civilian morale and thus provoke a terrorized population into pressuring their government to surrender.Footnote 39 In fact, the reverse occurred. Terror from the skies and a heightened sense of victimhood had the effect of stiffening the resolve of Germany's civilians to keep supporting their government's war efforts.Footnote 40 This experience gives reason to suppose that the same kind of response could be inadvertently induced in the context of the Russo-Ukrainian war. Indiscriminate drone strikes, though intended to bring the achievement of Ukrainian self-defense closer, might have the opposite effect: empowering Putin by galvanizing prowar sentiment among ordinary Russians.
Beyond this, if Ukrainian drone attacks inside Russia also increase the risk of conflict escalation, the war's overall consequences could be even worse. Whether or not Kyiv intends its attacks against Russian cities to be indiscriminate, the very occurrence of civilian harm could still exacerbate an angry dynamic of tit-for-tat retribution. It is therefore concerning that, since August 2023, both Russia and Ukraine have been angrily denouncing each other's drone strikes as “terrorist” attacks.Footnote 41 If mutual outrage caused these belligerents to become more ruthless and reckless, the scale and severity of the conflict could escalate, and the resulting damage could eventually be far-reaching. If the war spiraled out of control,Footnote 42 the people of other countries would also be endangered once their governments were strategically compelled to become militarily involved. And, if nuclear-armed states in Europe were then drawn into conflict with nuclear-armed Russia, the potential human costs would be incalculably high.Footnote 43
Conclusion
A belligerent with a just cause for war is not permitted to pursue that cause in any manner it sees fit and at all costs. This is because ad bellum rectitude has no bearing upon the universal requirement for in bello restraint. Although Russia was undoubtedly wrong to invade its neighbor, Ukraine still has a moral responsibility to avoid harming civilians when violently defending itself. While struggling to make on-the-ground progress in driving out the invaders, the Ukrainian government has sought also to fight back aerially on its enemy's home territory. Drone technology has enabled the attacking of targets deep inside Russia in the absence of other long-range weapons. However, an important distinction must be drawn between what President Zelenskyy has referred to as “symbolic centres” and “military bases.”Footnote 44 To the extent that the former are nonmilitary, it would be morally wrong to attack them with the intention of bringing wartime violence to Russian civilians. All civilians are nonliable to attack because they do not pose a military threat. Any injustices committed by those civilians’ political leaders or military personnel are irrelevant in this regard. If, despite this, the Ukrainian government were to use its drones as instruments of demoralization, such use would only be made more wrong by its likely ineffectiveness. Historical experience and current circumstances inside Russia suggest that anti-civilian air strikes would do little or nothing to advance Ukraine's just cause of self-defense. And, if such action increased the risk of conflict escalation, it could even be counterproductive.
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