The Election of Pope Leo XIV: Implications for the Holy See’s Diplomacy in the War in Ukraine

The election of a new Pope is never a merely internal affair of the Catholic Church. It is a global event, one that can subtly but significantly reshape the contours of international diplomacy. With the appointment on 8 May 2025 of Pope Leo XIV, formerly Cardinal Robert Francis Prevost of the United States, the Vatican enters a new phase of moral and diplomatic engagement. Among the most pressing international issues where the Holy See’s voice may exert influence is the ongoing war in Ukraine.

Here we consider how the background, nationality, and known positions of the new Pope might affect the Vatican’s approach to the conflict, and whether we are likely to see continuity or change in the tone and substance of its diplomacy.

A Pope from the United States

Pope Leo XIV is the first American to occupy the Chair of St. Peter. Born in Chicago in 1955 to a devout Catholic family of working-class roots, he entered the Augustinian Order and spent decades as a missionary and pastoral leader in Latin America, particularly in Peru. In 2020, he was called to Rome by Pope Francis to serve in high-level administrative roles, culminating in his appointment as Prefect of the Dicastery for Bishops.

This unusual combination—an American upbringing, Latin American pastoral experience, and senior curial authority—gives Pope Leo XIV a uniquely global perspective. Unlike his predecessor, whose Jesuit background and Argentine roots gave his foreign policy a Global South inflection, Leo XIV may be inclined to view the war in Ukraine through a more Atlanticist lens. His American origin does not automatically make him pro-NATO or hawkish, but it may increase his sensitivity to the stakes of the conflict for European security and international law.

The Francis Legacy and a Delicate Inheritance

Pope Francis’s approach to Ukraine was often described as frustratingly ambivalent by Kyiv and its allies. While he consistently called for peace, condemned the suffering of innocents, and offered humanitarian support, he often avoided explicit attribution of blame. His controversial suggestion in 2024 that Ukraine should consider raising a “white flag” to negotiate peace—a comment that sparked outrage—exemplified his deep commitment to ending violence, but also a perceived naïveté about the nature of Russian aggression.

Pope Leo XIV inherits this legacy of caution and complexity. But the initial signals from his pontificate suggest a possible shift in tone. In his first major public address following his election, he declared “Justice and peace are not enemies; peace built on injustice is a lie”. This carefully chosen phrasing may be read as a subtle rebuke of false equivalencies between aggressor and victim—a signal that the Holy See under Leo XIV may adopt a firmer stance on Ukraine.

Ukraine and the Moral Authority of the Papacy

For Kyiv, the papacy holds an outsised moral weight. Ukraine is home to a significant Catholic minority, especially in the west, where the Ukrainian Greek Catholic Church (UGCC) maintains strong loyalties to the Vatican. The UGCC has been outspoken in its condemnation of Russian aggression and in its support for Ukraine’s sovereignty and European path.

There is reason to believe that Pope Leo XIV may be more responsive to their appeals than Francis was. As a bishop in Peru, Leo XIV was known for aligning with local churches under pressure from political forces. He frequently spoke out on issues of justice, indigenous rights and government accountability. His willingness to trust the judgment of local hierarchies bodes well for stronger support for the UGCC and, by extension, a firmer Vatican line on the war.

The Holy See and Global Mediation

The Vatican is not a superpower in the conventional sense, but it plays an outsized role in backchannel diplomacy. Under Pope Francis, the Holy See offered itself repeatedly as a mediator in the Ukraine war, but its proposals were often viewed with scepticism due to perceived impartiality bordering on indecision.

Pope Leo XIV may recalibrate the Vatican’s peacemaking efforts to emphasise justice-based resolution rather than premature reconciliation. While he is unlikely to endorse military action, his American cultural and ecclesial context may give him a clearer understanding of the importance of deterrence, sovereignty and alliance-based security.

This could also position the Holy See to engage more effectively with transatlantic powers—especially the United States, Germany, and France—as well as moderate countries in the Global South, in shaping a future diplomatic path for Ukraine.

The Russian Orthodox Factor

A potential tension point remains the Vatican’s ecumenical relationship with the Russian Orthodox Church (ROC). Under Francis, the Vatican made significant efforts to keep lines of dialogue open with Patriarch Kirill, even as the ROC increasingly aligned itself with Kremlin narratives. Pope Leo XIV may be less inclined to prioritise this relationship if it continues to function as a de facto support system for Russian imperialism.

Any visible papal move to support Ukraine more openly, condemn the invasion, or praise the Ukrainian Church’s role in national resilience, may provoke protests from Moscow; but it would also bolster the Vatican’s credibility in Eastern Europe and among defenders of international law.

Conclusion: A Papacy With Diplomatic Potential

It is too early to predict with certainty how Pope Leo XIV will reshape the Holy See’s diplomatic profile in the context of the Ukraine war. However his background suggests a capacity for moral clarity, solidarity with suffering peoples and a cautious but principled engagement with political realities.

If Pope Francis offered the world a peacemaking papacy rooted in mercy, Pope Leo XIV may offer a vision of peace rooted in justice. Such a papacy could be a vital source of hope not only for Ukrainians, but for all who look to moral authority to counter aggression and affirm human dignity in times of war.