Pope Leo XIV's decision to declare the traditionalist Society of Saint Pius X (SSPX) in schism and excommunicate its bishops and priests has thrust one of Catholicism's most controversial movements back into the spotlight.
While the immediate dispute centres on papal authority and the unauthorised consecration of four bishops, the SSPX's decades-long rejection of the Second Vatican Council also touches on the Catholic Church's modern teaching on Judaism, Islam, religious freedom and interfaith dialogue.
Those theological disagreements have given the movement a distinctive position on issues ranging from Zionism and the modern State of Israel to relations with Jews and Muslims.
Unlike the Protestant evangelical currents of Christian Zionism that has become influential in much of the US, the SSPX rejects the idea that the establishment of Israel fulfils biblical prophecy, while also opposing many of the Church's post-war reforms governing relations with other faiths.
The New Arab looks at what the SSPX is and what it believes about Israel, Zionism, Jews and Muslims – and why those views have become part of its rupture with the Vatican.
More than the Latin Mass
Founded in 1970 by French Archbishop Marcel Lefebvre, the SSPX was established in opposition to reforms introduced by the Second Vatican Council between 1962 and 1965.
Although best known for preserving the Traditional Latin Mass, the society's objections extend far beyond liturgy.
It rejects or sharply criticises aspects of Vatican II concerning religious liberty, ecumenism and dialogue with other religions, arguing that the council has diluted centuries of Catholic teaching in pursuit of modernity.
The Vatican's latest sanctions, however, were not imposed because of those beliefs. Rather, they followed the SSPX's decision to consecrate bishops without papal approval, a move regarded under canon law as a direct challenge to the Pope's authority.
It is also important to distinguish between the society's leadership and those who worship at its chapels. Many Catholics attend SSPX churches because of their attachment to the Traditional Latin Mass or traditional spirituality rather than because they share all the theological or political positions associated with the movement.
The 'New Israel'
One of the most misunderstood aspects of the debate concerns Catholic teaching on Judaism.
For centuries, the Catholic Church taught that it is the fulfilment of God's covenant with Israel through Jesus Christ, often describing itself as the "New Israel".
This has frequently been labelled "supersessionism" or "replacement theology", although many theologians consider the latter term an oversimplification.
That doctrine did not disappear after Vatican II.
Instead, the council's landmark declaration Nostra Aetate transformed the Church's relationship with the Jewish people.
It rejected the idea that Jews collectively bear responsibility for the crucifixion of Jesus, condemned antisemitism and encouraged dialogue between Catholics and Jews while maintaining Christianity's central theological claims.
The SSPX argues that these developments weakened the Church's traditional missionary mission and blurred the distinctive truth of Catholicism.
The Vatican, by contrast, regards them as an authentic development of doctrine rather than a break with historic Church teaching.
Zionism without prophecy
Those theological differences also shape the SSPX's approach to Israel and Zionism .
Unlike many American evangelical Protestants, the society rejects dispensationalism – a nineteenth-century Protestant belief that often interprets the modern State of Israel as fulfilling biblical prophecy and occupying a central role in God's plan for the end times.
Traditional Catholic theology has never embraced that interpretation, instead distinguishing between the biblical people of Israel and the modern Israeli state.
As a result, criticism of political Zionism within traditionalist Catholic circles generally stems from theological or historical arguments rather than evangelical beliefs about biblical prophecy.
That does not necessarily make the SSPX pro-Palestinian, but it does place it at odds with the Christian Zionist movement that has become influential in US politics and among many supporters of Israel.
Islam after Vatican II
The society's disagreements with Vatican II extend beyond Judaism.
Nostra Aetate describes Muslims as worshipping one God and calls for dialogue and cooperation between Christians and Muslims while acknowledging profound theological differences.
The SSPX has consistently criticised that approach, arguing that it risks religious indifferentism by downplaying the differences between Christianity and Islam. Instead, it advocates a more traditional approach centred on evangelisation rather than interfaith dialogue.
Holocaust controversy
The SSPX's reputation suffered lasting damage in 2009 when one of its bishops, Richard Williamson, denied key facts about the Holocaust shortly before Pope Benedict XVI lifted the excommunications imposed on bishops ordained by Lefebvre in 1988.
The decision provoked international outrage and overshadowed Benedict's attempt to reconcile the society with Rome.
The SSPX later distanced itself from Williamson's Holocaust denial and eventually expelled him. Nevertheless, the affair cemented the movement's association with antisemitism in the eyes of many critics, even though Williamson's views never formed part of official SSPX teaching.