This essay assesses the morality of Ukraine's use of drones to attack targets inside Russia. Following its invasion by Russian forces, Ukraine has had a just cause to wage a war of self-defense. However, its efforts to achieve that cause remain subject to moral limits. Even a state that has been unjustly attacked may not, for example, respond by deliberately targeting the attacking state's civilian population. To do so would violate the jus in bello principle of discrimination. The essay first describes how drone technology has frequently enabled long-range strikes against Russian military assets as well as other targets inside cities. It then explains why it would be morally wrong for Ukraine to attack its enemy's population centers. First, Russian civilians are not liable to attack, and this nonliability is undiminished by the injustice of Russia's invasion or by any in bello wrongs committed by the Russian military. Second, attacking Russian cities with drones would arguably achieve little or no self-defensive benefit for Ukraine, and it could even be counterproductive.

The Russia-Ukraine war demonstrates the crucial role of technology in modern warfare. The use of digital networks, information infrastructure, space technology, and artificial intelligence has distinct military advantages, but raises challenges as well. This essay focuses on the way it exacerbates a rather familiar challenge: the “civilianization of warfare.” Today's high-technology warfare lowers the threshold for civilian participation in the war effort. A notable example is the widespread use of smartphone apps by Ukrainian civilians, who thereby help the armed forces defend against Russian aggression. Through the lenses of international humanitarian law, conventional just war theory, and revisionist just war theory, this essay evaluates the normative dimensions of such civilian participation. The analysis shows that civilians can lose their legal protections when they use these apps to directly participate in hostilities, and this loss of immunity can be justified by Michael Walzer's conventional just war theory. Revisionism, however, puts the justness of the war at the forefront, and so sheds doubt on the moral liability of Ukrainian civilians. Considering the broader implications, including the blurring combatant-civilian distinction, indicates that such civilianization of warfare should not be welcomed; the risks will often outweigh the benefits. At a minimum, states ought to exercise restraint in mobilizing civilians and inform them of the implications of their actions.

Ukraine's war of self-defense against Russia is one of the clearest examples of a nation fighting a just war in recent history. Ukraine is clearly entitled to defend itself, and Russia is clearly obligated to cease hostilities, withdraw troops, and make repair. In light of this, some of the most salient moral questions related to Russia's war of aggression in Ukraine involve the international community; namely, what moral duties it has toward Ukraine, especially in light of Russia's extreme and pervasive human rights abuses. The first section of the essay argues that there is a pro tanto moral duty to intervene militarily in Ukraine to stop Russian human rights abuses and ensure that Ukraine achieves a military victory. This duty is grounded in duties of rescue, promissory obligations, and reliance obligations, as well as duties to nations’ own citizens and to the international community. The second section of the essay argues that the most relevant consideration in determining whether there is an all-things-considered duty for the international community to intervene militarily in Ukraine is Russia's nuclear coercion and the associated risk of nuclear war. This section highlights the nuclear risks involved in compliance with Russian nuclear coercion, which I argue have been neglected in prominent discussions. The moral stakes involved in this determination are very high, and succumbing to Russian nuclear coercion in the face of massive human rights violations would set a dangerous precedent. Any course of action should be guided by a thorough analysis of all the risks involved, both nuclear and moral.

One of the most pronounced features of the war in Ukraine has been the heavy reliance of the Russian forces on convict-soldiers, most notably by the private military and security company (PMSC) the Wagner Group. In this essay, I explore the ethical problems with using convict-soldiers and assess how using them compares to other military arrangements, such as conscription or an all-volunteer force. Overall, I argue that the central issue with using prisoners to fight wars is their perceived expendability. To do this, I present three arguments. First, although many prisoners have been under major duress, using convict-soldiers may be somewhat preferable to using conscripts in this regard. Second, convict-soldiers are more likely to be subject to human rights abuses than other types of soldiers and this should be seen as the main problem with their use. Third, convict-soldiers’ liability to lethal force for fighting in an unjust war does not render it permissible to treat them as expendable.

Since commencing its illegal invasion in 2022, the Russian military and authorities have committed numerous war crimes against the people of Ukraine. These include the mutilation and execution of combatants; the torture, kidnapping, forced expulsion, rape, and massacre of civilians; and indiscriminate attacks on densely populated areas. In this essay, I evaluate the strategic implications of this misconduct, focusing exclusively on Western responses. I argue that war crimes can and often do negatively impact the strategic goals of the perpetrator, but whether and how this occurs is rarely governed exclusively by the offending action. Western perceptions of battlefield atrocity, shaped as they are by identity, race, and politics, may radically shift from one context to another. In the case of the Russia-Ukraine war, the status of both the participants and the conflict itself has helped inculcate a particular sensitivity among Western actors to the battlefield criminality of Russia. Drawing on evidence from the 2022 Bucha massacre and the ongoing bombing of Ukrainian civilians, I argue that Russian misconduct has consolidated Western support for the Ukrainian military effort, politically, diplomatically, and materially.

Now in its third year, the Russian war of aggression against Ukraine remains at the very top of the international security agenda. This conflict has largely refocused the West's attention away from the counterterrorism and counterinsurgency campaigns that followed the terrorist attacks of September 11, 2001. In February 2022, German chancellor Olaf Scholz went so far as to declare that the invasion signaled a zeitenwende, or “dawn of a new era.”1 Russia's aggression and the threat of having to fight a peer or near-peer competitor raises difficult questions, many of which are ethical in nature. The essays gathered in this roundtable seek to provide answers to some of those questions. They are the result of a workshop I organized for the King's College London Centre for Military Ethics in October 2023. One of my ambitions for this workshop was to put leading academics working on the ethics of war into discussion with military practitioners, making sure to include Ukrainian voices. I was very fortunate to succeed in these objectives, and I am convinced that the published essays have benefited enormously from our conversations.

I have an idea that some men are born out of their due place. Accident has cast them amid certain surroundings, but they have always a nostalgia for a home they know not. They are strangers in their birthplace … Perhaps it is this sense of strangeness that sends men far and wide in the search for something permanent, to which they may attach themselves … Sometimes a man hits upon a place to which he mysteriously feels that he belongs …