American pressure on Ukraine to negotiate with an aggressor that shows little interest in peace reflects an argument that has become increasingly familiar – that, with mounting casualties and an ever-present risk of escalation, it is no longer proportionate for Ukraine to continue fighting Russia or for western democracies to continue supplying it with arms. By contrast, Kyiv’s supporters and most Ukrainians maintain that resistance should continue at least until Ukrainian autonomy is fully guaranteed. These opposing views reflect deeper philosophical uncertainties about what defensive wars are really about.
Philosophers often turn to personal self-defence scenarios to help explain wars such as Ukraine’s. They use them to illustrate the most important moral principles, which can then help them think about the bigger, more controversial questions such as, at what point should Kyiv stop fighting?
The scenario they most often cite involves an innocent person defending themselves against murder. It’s a case that resonates widely with the public – surely if killing is ever permissible, it is when innocent people are themselves threatened with wrongful killing. But when it comes to wars such as Ukraine’s, this is the wrong place to start. A better starting point is defence against slavery.
Defending against murder and defending against slavery are different in important ways. And yet, intuitively, both meet the standard of proportionality – defensive killing wouldn’t be excessive in either case, if it was necessary. One reason for this has to do with what the two threats share. Both murderers and enslavers typically arrogate to themselves the uncontrolled power to inflict harm. But enslavement illustrates this sort of power much more vividly. For sure, murderers exploit strength, speed or surprise to render victims defenceless. Yet their power to kill is often fleeting – it disappears as soon as the victim expires. By contrast, as abolitionists such as Frederick Douglass attested, slavery permanently suspends the untrammelled power to mutilate and kill over the heads of the enslaved.
It is the wrongful seizure of the power to kill (rather than the probability of death itself) that explains why defensive killing is justifiable against both murder and slavery. But defending against enslavement is a better analogy for Ukraine because it mirrors more closely what the war against Russia is about.
In contrast to someone defending themselves against murder, Ukraine’s motivation in fighting isn’t to save lives. Far from it. In February 2022, the decision to fight inevitably sacrificed many lives. The value for which Ukrainians made those sacrifices wasn’t life itself – it was freedom from the uncontrolled power over life and death that Russian forces seek to project into their country. This is a war about freedom from domination.
In the perspective that this opens up, just war resists what Simone Weil called “that other force, the one that does not kill, which is to say, the force that doesn’t kill yet. It surely will kill, or maybe it will,” but in the meantime “it simply hangs there, suspended over the person whom it can kill at any moment”. When regimes hold this kind of uncontrolled power, it is possible for them to maim and kill at will. At scale, such domination can pin down an entire people, condemning it to what republican thinkers denounce as political slavery.
From this standpoint, just war isn’t about trying to reduce numbers of probable deaths – it is about defeating the power to inflict death at will. A republican theory of just war grounded in the great historical examples of emancipatory war in Haiti (1791-1804) and the USA (1861-65) therefore points to a very different moral calculus. And this makes a big difference when we turn to Ukraine’s question of the moment – when and how to end a just war.
Just war theorists generally agree that even a war that was justified at the outset can become unjust if mounting costs eventually exceed the value for which it is being fought. Darrel Moellendorf describes this as blowing a state’s “proportionality budget”. It is this idea that critics implicitly invoke when they argue that the costs of Ukraine’s war must by now have exceeded the value of successful defence.
According to the abolitionist analogy, however, we are unlikely to have reached that point – nor will we reach it any time soon. It is true that fighting has cost many thousands of lives so far, and continuing will cost many thousands more. But, as we have seen, the aim of the Ukrainian resistance isn’t to save a specifiable number of people from violent death – it is to save people from domination. So at what point would further fighting tip the scales, rendering war disproportionate?
To answer this, consider the threat. This is a war against uncontrolled destructive power, which Russian forces seek to project across as much of Ukraine as possible. If resistance fails and Russia establishes control over the whole state, then no Ukrainian will be free from it. Of course, many will be lucky and the disappearances, torture and arbitrary killings characteristic of Russian occupation will pass them by. But all will remain trapped under the shadow of Weil’s “force that does not kill yet”.
A war against Russian domination therefore defends everyone. Currently, that means tens of millions of Ukrainians. This is to say nothing of the Moldovans, Lithuanians, Estonians, Latvians and many other millions of Europeans facing exposure to the same untrammelled power if Ukraine is thrown to the wolves.
If there is a proportionality budget in the Ukraine war, then it is nearly limitless. Whether Kyiv’s resistance (and western support) remains morally justifiable is fundamentally a matter of how much Ukraine and its people value their freedom and are prepared to sacrifice for it.
Exhaustion, defeat or permanent military stalemate may eventually force Kyiv to compromise. But, for now, until a credible offer of peace is on offer with military guarantees securing Ukrainians against the arbitrary, destructive will of Russia, there can be no moral argument for insisting that Kyiv calls its fight to an end or that democratic allies withdraw military support.
[ Ukrainian language as a weapon of war: ‘It’s a form of resistance’Opens in new window ]
Christopher Finlay is professor in political theory at Durham University. His latest book, The Philosophy of Force: Violence, Domination, and the Ethics of Republican War, appears this April with Oxford University Press
