Pope Leo XIV’s critics ask why the church should enter political disputes. Catholic tradition poses the prior question: by what moral law is political power to be judged?
When Pope Leo XIV told journalists in early June enroute to Spain that the conflict in Iran did not meet the church’s criteria for a just war, he reignited a perennial debate about whether the church should speak into matters of public policy at all.
US Vice President JD Vance had already given voice to that concern in April when he suggested the Vatican should “stick to matters of morality” and leave American public policy to the President.
At first glance Vance offered a distinction many Catholics might initially find reasonable. The Pope does not command the armed forces of the United States, determine its borders, or possess the technical competence required to settle every question of economic and foreign policy.
The church recognises the legitimate authority of the state, and Catholic social teaching leaves considerable room for prudential disagreement about the means by which governments pursue security, order, and the common good.
The difficulty is that Vance’s distinction cannot bear the weight placed upon it. War, migration, the treatment of civilians, and the exercise of political power are themselves matters of morality. Government may determine policy, but it cannot determine whether justice exists, what human dignity means, or when the innocent may be sacrificed to national interest.
Pope Leo has stated the distinction plainly: ‘I am not a politician’, he told journalists in April, before explaining that he would continue to speak against war because he speaks from the Gospel.
The question, therefore, is not whether the Pope should become a political actor. He should not. It is whether political action may place itself beyond moral judgement. Catholic teaching has always answered that question in the negative.
The state possesses a proper and necessary authority. St Paul’s instruction concerning obedience to rulers cannot be discarded whenever a government disappoints us, nor can public order be treated as a regrettable concession to fallen humanity. As the Catechism of the Catholic Church teaches, every human community requires authority, whose proper purpose is the common good.
Yet authority is legitimate only when it employs morally acceptable means. Political power must operate within the moral order, respect the human person, and secure the peace of the community.
That qualification is decisive. A democratic mandate does not turn an unjust act into a just one. A parliamentary majority cannot repeal the natural law, nor does national sovereignty release rulers from responsibility before God. Political communities possess independence within their proper sphere, but they do not create the human dignity they are bound to defend.
The church’s intervention in public affairs begins at this boundary. She does not ordinarily dictate the technical means by which policy should be implemented. She forms consciences, identifies moral principles, defends those whose interests are easily ignored, and reminds rulers that power is never self-justifying.
Catholics may disagree about troop deployments, immigration numbers, taxation, or diplomatic strategy. They may not maintain that the treatment of human beings becomes morally neutral once it is classified as public policy.
An early and formidable expression of this principle came in 390, after troops acting under Emperor Theodosius I massacred inhabitants of Thessalonica. Ambrose of Milan did not deny the emperor’s office, nor did he seek to govern the empire in his place.
He addressed Theodosius as his pastor, refusing to offer the Eucharistic sacrifice in the emperor’s presence until repentance had occurred. In Epistle 51, §17, Ambrose stated the order of his loyalties with austere clarity: ‘I place God before you’.
Ambrose’s position was neither sedition nor episcopal ambition. He recognised that imperial authority remained subject to judgement precisely because it was real authority. Theodosius’s command carried consequences for thousands of lives.
It could not be excused as a technical decision reserved to the state. Ambrose did not seize the imperial sword.
He insisted that the emperor examine how it had been used.
Martin Luther King Jr.’s description of the church as neither the master nor the servant of the state, but its conscience, belongs within this older Christian understanding. The Church becomes the state’s master when she seeks direct control of government.
She becomes its servant when she blesses power in exchange for protection or influence. She becomes its tool when politicians invoke Christian teaching selectively, welcoming it on abortion or religious liberty while dismissing it on war, migrants, poverty, or the treatment of prisoners – or vice versa.
The church can fulfil her proper office only when she remains sufficiently independent to address every political allegiance, including those favoured by her own members.
Pope Leo’s teaching on war should be read in this light. In Magnifica Humanitas, §192, he argues that just-war theory has too often been employed to justify forms of warfare it was intended to constrain.
He does not abolish the right of legitimate self-defence.
He expressly preserves it ‘in the strictest sense’. His concern is directed towards a political culture in which war is increasingly normalised, civilians disappear into strategic calculations, and remote or autonomous weapons make killing easier to initiate and harder to assign to a responsible moral agent.
This argument belongs to the history of the tradition rather than standing outside it. Augustine did not devise just-war reasoning to make violence respectable. He sought to subject warfare to moral judgement. Legitimate authority, just cause, and right intention were restraints upon violence, not presumptions in its favour.
War might sometimes be endured as a tragic necessity, but victory could not establish righteousness, and military success did not disclose the will of God.
My own research on the transmission of crusading ideas in east Central Europe has repeatedly brought me back to the danger that arises when this restraint is replaced by religious certainty. A revealing instance occurred during the Second Crusade.
At Frankfurt in March 1147, northern German nobles proposed that, rather than travel to the Holy Land, they should campaign against the pagan Slavs living beyond the Elbe. Bernard of Clairvaux promised them the same indulgence granted to those journeying towards Jerusalem, and Pope Eugenius III subsequently authorised the expedition.
The language associated with the campaign shows how quickly a regional war could be transformed by crusade preaching. Bernard wrote of the conversion or destruction of the targeted peoples, while the Magdeburg Annals described an army setting out beneath the cross either to bring the Slavs into Christianity or to destroy them.
The campaign reached Szczecin, where the inhabitants and their bishop reportedly had to explain to the crusaders that the town had already been converted through the mission of Otto of Bamberg.
That episode deserves more than a passing denunciation. The crusaders did not leave ordinary political interests behind when they took the cross. Saxon expansion, Danish ambitions, Polish participation, local rivalries, missionary aspirations, and expectations of material advantage accompanied the religious language.
Yet papal authorisation and indulgenced preaching altered the moral character attributed to the campaign. Violence could now be presented as penitential service. The cross sewn onto clothing did more than identify a soldier. It interpreted his action.
This is why the authority to sanctify violence must be treated with particular caution. Once war is proclaimed as God’s cause, hesitation can appear faithless, compromise can look like betrayal, and the suffering of the enemy can be absorbed into a story of providential necessity.
The medieval record does not require Catholics to distrust the papacy. It teaches why the papacy must exercise its authority over questions of war with grave restraint. The same office that once authorised crusades possesses both the responsibility and the historical memory required to warn against the sacralisation of modern conflict.
Pope Leo’s insistence upon peace is therefore not an accommodation to secular fashion. It reflects a traditional Christian suspicion of rulers who identify their own strategic interests too readily with divine justice. In April, he called the protection of civilian populations a moral obligation grounded in conscience and recognised in international law.
He has applied similar reasoning to migration, describing it as a moral and legal question while recognising that justice requires both humane reception and attention to the conditions that force people to leave their homes.
None of this supplies a complete military, diplomatic, or immigration policy. It establishes the moral conditions within which such policies must be considered. Governments retain their responsibility to govern. Catholics retain their freedom to assess prudential means. The Successor of Peter retains the duty to teach, even when that teaching disturbs political loyalties.
A defence of political order cannot become a defence of political absolutism. Authority deserves obedience because it serves an order it did not create. The papacy serves that same order differently: by guarding the faith, forming conscience, and recalling rulers to the moral law. When Pope Leo speaks about the human cost of war, he does not claim the authority of a president or general. He exercises the authority of a pastor.
Ambrose’s words to Theodosius remain the proper measure: God comes before the emperor. The church does not govern the state, but neither does she receive from the state permission to proclaim the Gospel.
