The saying that ‘the first casualty of war is truth’ is most commonly attributed to the ancient Greek playwright Aeschylus. Perhaps he should have said that war’s first casualty is rationality. Nothing stirs the emotions of men like the sight of the latest hardware of war: F-35 fighter planes, hypersonic missiles, MOAB bombs and the like, or one’s enemies finally getting it in the neck. It is at times like this that the classic just war theory, formulated by St Augustine, St Thomas Aquinas and the Spanish School of Salamanca, among others, proves itself to be a treasure for the Church, allowing us to think straight about war.
This just war theory informs paragraph 2309 of the Catechism of the Catholic Church and the ‘strict conditions’ requiring ‘rigorous consideration’ before defensive military force can be used legitimately. These four conditions are essentially the following: just cause, last resort, probability of success and proportionality.
On February 28, 2026, the United States and Israel launched a joint military operation against Iran, dubbed ‘Operation Epic Fury’. In the initial attacks they carried out 900 strikes targeting Iranian missiles, air defence systems, military infrastructure and leadership sites, killing Iran’s Supreme Leader, Ali Khamenei, along with other officials.
The world has been left uneasy. We hope that the leaders of the United States and Israel know what they are doing, for, as paragraph 2309 puts it: ‘The evaluation of these conditions for moral legitimacy belongs to the prudential judgment of those who have responsibility for the common good.’ Prudential judgments require the weighing up of all the relevant information at hand regarding a proposed course of action – information to which we, the hoi polloi, are for the most part not privy. Given the incredible complexity of the geopolitical and military issues surrounding war, it is very difficult to attain any great certainty about the legitimacy or otherwise of a particular military action, and so our own judgments are always limited by this lack of knowledge.
That said, it might be useful to examine what some of the main Catholic commentators have been saying with regard to this war, in the light of the ‘strict conditions’ outlined in the Catechism of the Catholic Church.
Regarding the requirement for a just cause – that ‘the damage inflicted by the aggressor on the nation or community of nations must be lasting, grave and certain’ – there is little doubt that Iran has been sowing chaos throughout the Middle East and beyond through its terrorist proxy groups such as Hamas, Hezbollah and the Houthis, even though more often than not their victim has been Israel rather than the United States, and Israel is well able to look after itself, as Edward Feser points out. President Donald Trump’s claim that ‘our objective is to defend the American people by eliminating imminent threats from the Iranian regime’ appears to be stretching it.
Back in July, George Weigel supported the attacks on the Iranian nuclear infrastructure, saying that ‘depriving the Iranian regime of the vast, destructive capability of nuclear weapons was imperative, morally and strategically. In this case, when diplomacy had clearly failed, various forms of aggression were underway, and the regime’s intentions were quite clear, pre-emption was morally justifiable, even if the medium- and long-term outcome of that justifiable action cannot be known with certainty now.’
One wonders, however, whether the threat of nuclear action by Iran was more remote than proximate, in which case the US–Israeli action looks more preventive (eliminating a possible future threat) than pre-emptive (responding to an imminent attack), the latter being morally defensible but the former risking a recipe for world anarchy, as Cardinal Pietro Parolin, the Vatican’s Secretary of State, recently pointed out.
And is this military action a last resort? Did it take place only after ‘all other means of putting an end to it … were shown to be impractical or ineffective’, as the second condition stipulates? This is debatable, though Robert Royal thinks that military action has been justified by the failure of the world’s ‘decades of “dialogue” with Iran’ to stop its ‘developing long-range missiles, enriching uranium and sponsoring terrorism – for half a century’.
We can only assume that the US–Israeli alliance was convinced before acting that the ‘serious prospects of success’ – the third condition required in the Catechism – did indeed exist, even if what constitutes ‘success’ seems a bit unclear. There appear to be several contenders for measuring success: the destruction of Iran’s capacity to produce and deploy nuclear weapons; the destruction of the Iranian ballistic missile programme and of its navy; the reduction of Iran’s capacity to fund and supply its proxies; and lastly the freeing of the Iranian people from theocratic tyranny.
But already it appears that this war least clearly fulfils the condition of proportionality, that ‘the use of arms must not produce evils and disorders graver than the evil to be eliminated’. An assessment of proportionality evaluates foreseeable consequences. Presumably it would not have been difficult to foresee at least some of the chaos that might emerge from this military action.
As I write, just over a week after the military action against Iran, the Middle East is in turmoil, world oil prices have spiralled and – ominously – Vladimir Putin has offered ‘unwavering support’ to the new Iranian leader. During his March 8 Angelus address, Pope Leo warned that ‘in addition to the episodes of violence and devastation, as well as the widespread climate of hatred and fear, there is also the concern that the conflict will spread and that other countries in the region, including beloved Lebanon, may again sink back into instability’.
We fail to listen to such warnings at our peril, and unfortunately we have been here before. The 2003 toppling of Saddam Hussein’s regime in Iraq produced much greater evils than it ever solved: a sectarian civil war in Iraq (2006–2008) with tens of thousands killed, the rise of ISIS, the expansion of Iranian influence in the Middle East and the flight of the great majority of Christians from Iraq – one of the greatest collapses of Christian communities in the Middle East since antiquity. Famously, the Holy See, under Pope St John Paul II, had vigorously opposed the US-led invasion and predicted much of what would be its outcome.
The Catechism is right to say that defensive military action always requires ‘rigorous consideration’ before being undertaken, and as the consequences of the attack on Iran begin to manifest themselves, I for one have a niggling feeling that we might be looking at a repeat of the 2003 debacle.
