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Should Ireland support Ukraine militarily? Try answering ‘No’

Unthinkable: ‘Just war theory’ is not a licence for standing on the sidelines and hoping for peace

Russia’s invasion of Ukraine has thrust a moral dilemma on the outside world: should other states intervene militarily?

The ethics of conflict have been long studied under “just war theory” (JWT) – a broad set of principles that have been refined over centuries from ancient civilisations, through Saint Augustine and Thomas Aquinas, to the present day. The right to go to war – jus ad bellum – is established if the following criteria are met: (1) just cause, (2) competent authority, (3) comparative justice – ie, the balance of righteousness falls on one side, (4) right intention, (5) reasonable prospect of success, (6) last resort, and (7) proportionality.

But is a theory that was largely crafted around Europe’s medieval wars fit for purpose in the modern era of false flag operations, disinformation campaigns and cyberattacks? And does the rule book go out the window when faced with as deceitful and ruthless a foe as Vladimir Putin?

"JWT does help us, I think, in cases like this. But it's important not to ask too much of the theory," says Christopher Finlay, author of Is Just War Possible? The current conflict throws up three general calculations, says the political philosopher, who hails from Omagh, studied at Trinity College Dublin and is now a professor at Durham University.


First, is Russia justified in waging war on Ukraine? This is easily answered in the negative.

Second, is Ukraine justified in fighting against Russia? While JWT “will lead us to be very sympathetic to Ukraine’s attempt at defensive war” under most criteria, it will “ask more difficult questions . . . in relation to proportionality and reasonable prospect of success,” says Finlay.


“If war is only justified when it is expected not to cost more (measured in terms of the value of innocent lives, and other related destruction, lost by fighting) than the values it preserves, then cases where a smaller, weaker state faces aggression from a much larger, better armed one are harder to judge.” Ultimately, however, “if many Ukrainians are willing to take risks and make sacrifices for the sake of their political freedom, then it means that war is more likely to satisfy a condition of proportionality”.

The third and trickiest question is whether the outside world is justified in intervening militarily?

“To my eye, what JWT is likely to say to someone like [US president Joe] Biden is the following: Ukraine is justified in waging defensive war against Russia – certainly as far as just cause and legitimate authority are concerned. But it will struggle to satisfy the success condition. . . and, as the chance of success diminishes over time, it seems increasingly disproportionate to persevere. So the question for Biden then is: should the US assist Ukraine in order to improve its chance of success and help it satisfy the condition of proportionality?”

Putin has for years been carrying out hybrid warfare, blending conventional military attacks with targeted assassination and economic sabotage

Biden, along with EU leaders, answered this question in the affirmative over the weekend, sending more military aid to Ukraine. Whether this can continue without the US “finding itself at war formally with Russia” is an open question, says Finlay. As for sending in US troops, “while it might have just cause, the wider consequences are potentially so severe that fighting is quite likely to be disproportionate”.

A starting point in all calculations is that war is bad – "always bad, since it involves death and injury to people, destruction of property and waste of human resources. There is nothing good about war," according to James G Murphy SJ, author of War's Ends: Human Rights, International Order, and the Ethics of Peace.

Under JWT, he says, outside intervention in Ukraine would be justified. “Russia has started the biggest war in Europe since 1945, with serious implications for the general peace of Europe.” However, intervention “would be imprudent, since it could lead to Nato-Russia war with Nato unprepared. . . That is probably enough to warrant not going to war”.

At the same time, he says, the US and UK created “a certain moral obligation” when they guaranteed the independence of Ukraine in 1994 in return for it giving up its nuclear weapons. To date, those Nato countries have failed to honour that duty. “For instance, president Obama refused to give anti-tank Javelin missiles to Ukraine in 2014 when it was first attacked by Russia.”

Murphy, who teaches at Loyola University Chicago, believes a key question is: “Would Nato be justified in preparing for war now – against the next Putin surprise?” This would mean “rearming itself dramatically and rapidly”, and stationing large numbers of US, UK, French, German and other troops in the frontline states of the Baltic republics including Poland and Slovakia. “The answer is ‘Yes’. More than that: it is not merely morally justified, it is probably morally obligatory for Nato to do so.”

Putin’s threat to respond to third-party interference with “consequences that you have never faced in your history” adds further menace. Should intervention be avoided if there is even the smallest risk of it increasing the likelihood of a nuclear war?

“I don’t think I’d go quite that far,” Finlay replies. “Certainly, if there’s a high risk of nuclear war, then it’s unlikely that intervention will be proportionate. But, then again, it partly depends on what you’re intervening to defend against: conventional warfare can reach almost unimaginably destructive levels even without recourse to nuclear weapons.

“As for ‘the smallest’ risks, we also have to bear in mind the risks sometimes arising from inaction. . . The key point would simply be that nuclear war is a risk we should always bear in mind, whichever way we’re thinking of turning.”

How to respond to Russian cyberattacks is another matter? “Because these don’t usually aim at or cause deaths or physical injury and destruction, it seems less likely that they can justify a warlike reply,” says Finlay. “But even if that’s usually true, JWT might still be relevant: it might be, for instance, that we need an ethics of pure cyberwar – after all, much of our life now is lived in and through virtual, IT-generated structures.

“We would surely want to defend ourselves against actions intended to damage these but doing so might require us to use cyberattacks against the source of the threat.” The principles of jus in bello – or proper conduct within war, a second strand of JWT – would need to be updated to manage the ethics of this.


"It's possible that 'cross-domain' actions could be justifiable in imaginable cases – ie armed force in reply to cyberattack." While he is "not an advocate" of this, he has researched conditions under which a reasonable case could be made.

Putin has for years been carrying out hybrid warfare, blending conventional military attacks with targeted assassination, economic sabotage and foreign electoral intervention. Is JWT out of date in the face of these new forms of aggression?

“The just war theory offers us something: it doesn’t work well for guerilla wars or insurrection wars, but it works partly,” Murphy replies. “And we have no other theory. Even in the sciences, no theory, however inadequate, is dumped unless a replacement – that is an improvement – is found.”

When it comes to practical decisions, those most affected by a crisis “should be given most weight”, the Jesuit priest adds. The people of Ukraine do not have “the luxury of inconclusive drawn-out academic debates”; war has already come to their homes.

Our neutrality is morally indefensible: it is a violation of solidarity with our neighbours and partners

“There is a common bias, often found among Catholic priests, and peace groups: that the more strictly the just war conditions are interpreted the better, and that one can’t go wrong in deciding not to fight and in opting for peace. Both are mistaken, and misunderstand the nature of the moral challenge that the risk of war presents,” Murphy says.

“It’s a caricature to imagine that people or countries want war ‘for its own sake’: nobody does. The issue is: are we Europeans prepared to sacrifice great goods for the sake of peace with – ie, submission to – a dictator?”

What of Ireland specifically? Would we be justified going to war with Russia. "No. Russia has not attacked us, nor is likely to. That's really a non-serious question," he replies. "Here's a serious one: would Ireland be justified in going to the support of other small European countries if they were attacked? Try answering 'No' to that: I can't justify it. I can't see any moral justification for Ireland refusing to support them. Not merely would Ireland be morally justified in giving material support to the likes of Lithuania, a small country that escaped the grip of an empire as Ireland did, I deem it morally obligatory for us to do so.

“Our neutrality is morally indefensible: it is a violation of solidarity with our neighbours and partners.”

Finlay is less certain on the matter. Neutrality is “probably” justifiable for some states at least some of the time. For certain countries, especially smaller ones, “a specialised role in brokering peace, mediating between powers, and so on, might be a better way to discharge their moral duties globally. And there might be other ways of contributing too that don’t involve engaging directly in armed conflict”.