On November 28, 2025, the Vatican released the following statement from Pope Leo XIV: “We must strongly reject the use of religion for justifying war, violence, or any form of fundamentalism or fanaticism. Instead, the paths to follow are those of fraternal encounter, dialogue and cooperation.” But since early 2026, however, Pope Leo has been dealing with a very specific Catholic fundamentalist problem.

 In the first week of February 2026, the Swiss-based Catholic fundamentalist group, The Society of St. Pius X, announced plans to consecrate new bishops without papal consent.

Founded in 1970 by the French Archbishop Marcel Lefebvre (1905–1991), The Society of St. Pius X prioritizes a pre-Vatican II, anti-Modernist stance, strictly adhering to the Tridentine Latin Mass and traditional Catholic doctrines. In 1988, Archbishop Lefebvre consecrated four bishops without papal consent, arguing that it was necessary for the survival of the church’s tradition. The Vatican promptly excommunicated Lefebvre and the four other bishops. In the years since the 1988 excommunication, as Nicole Winfeld reported via Religion News Service, on February 19, 2026, the Society of St. Pius X has continued to grow, with schools, parishes, and seminaries around the world. Today it has 733 priests, 264 seminarians, 145 religious brothers, 88 oblates, and 250 religious sisters.

In the United States, at least since the second decade of the twentieth century, the word “fundamentalism” has usually been understood as something quite specifically Protestant, militant, and American. Few people realize, however, that a militant and sectarian “fundamentalist” movement emerged within American Roman Catholicism in the decades after World War II. The focal point was the St. Benedict Center in Cambridge, Massachusetts, founded in 1940 to serve the growing number of Catholic students attending Harvard University and Radcliffe College.

Significant changes at St. Benedict Center came in 1943, however, when Leonard Feeney, S.J. (1897–1978) arrived as pastor. Feeney had been a literary editor at the Jesuit magazine America in the 1930s but, at St. Benedict Center, he gave incendiary speeches, leading Robert F. Kennedy (1925–1968), then a Harvard undergraduate, to write Archbishop Richard Cushing (1895-1970) of Boston requesting his removal.

Feeney had declared that in strongly Catholic Boston, he wanted to “rid our city of every coward liberal Catholic, Jew dog, Protestant brute, and 33rd degree Mason who is trying to suck the soul from good Catholics and sell the true faith for greenbacks.”

Feeney was excommunicated on February 13, 1953. Nevertheless, he and his followers crafted the paradigm for American Catholic fundamentalism as an anti-modern, reactive, and sectarian impulse that has been with us ever since.

A helpful book about American Catholic fundamentalism is Fr. Mark Massa’s Catholic Fundamentalism in America (Oxford University Press, 2025). Massa, a Jesuit Priest, is professor of theology at Boston College and for nine years was director of the Boisi Center for Religion and American Public Life. For the 2026–2027 academic year, he will be a visiting professor at Fordham University.

Massa recounts how American Catholic fundamentalists have reacted both to the teachings of the Second Vatican Council (1962-1965) and to the tensions of America’s pluralist, secular culture. Like their Protestant cousins, Catholic fundamentalists combine a sectarian understanding of religion with an aggressive anti-progressive stance. Their main enemies are not Protestants or secular Americans, but other Catholics who do not share their extreme views.

Like Protestant fundamentalists, Catholic fundamentalists have sought and found political conservatives with whom to make common cause on a range of issues, like the place of women in American culture, opposition to LGBTQ people, rejecting the value of pluralism within the Church and the larger culture, and rejecting the importance of cooperation with non-Catholics.

Contemporary Catholic fundamentalists merge their theological and political impulses into movements that go far beyond mere conservatism. Their fundamentalism is a rigid, ideological, and often militant approach that demands a return to an imagined pure, literal interpretation of foundational texts or beliefs.

They only listen to sources that they agree with. Their brains have stoped questioning. They no longer think for themselves. They obey their fundamentalist leaders, and have zero empathy for anyone outside their group,

Conservatism often treasures tradition, heritage, and “the way things were done” as a guiding, but sometimes flexible, framework. Fundamentalism goes farther by insisting on strict literalism and inerrancy of sacred texts and rejecting modern scholarly or contextual interpretations. Fundamentalism is dangerous because it fuels extremism, misogyny, and violence, threatening democratic values and social cohesion.

Fundamentalists view modern liberal culture as a corruption that must be erased and replaced with their specific, often archaic, ideology. While conservatives can work within democratic pluralistic frameworks and accept compromise, fundamentalists view compromise as a character flaw or a sin. Fundamentalists select and reinterpret certain specific past traditions to provide a sense of security against social change. But they really seek total control over society, including politics, culture, economics, and family life. They often adopt a combative, “war-like” stance toward opposing viewpoints, “them against us,” viewing “them” as treasonous.

By way of example, fundamentalists in the current U.S. presidential administration have embraced the “Great Replacement” theory, a far-right conspiracy theory that was first proposed by the French writer Renaud Camus (born 1946) in the late 1990s, and it has become increasingly mainstream within today’s Republican Party. The “Great Replacement” theory says that Brown and Black migration is destroying “western civilization.” It argues that such migration must be stopped and that Brown and Black people must be purged so that White Christians can dominate society and reinforce traditional religious and patriarchal hierarchies. These “Christians” ignore of course the historic fact that Jesus of Nazareth was certainly NOT a White-skinned European, but a Brown-skinned Middle Eastern Hebrew.

Contemporary fundamentalist-leaning Catholics are active in the incumbent presidential administration. Six of the nine U.S. Supreme Court Justices are Catholic, with a conservative majority. Individuals and groups associated with fundamentalist Catholicism are also among the key architects and supporters of Project 2025. The the architect of Project 2025, the Heritage Foundation’s president, has close ties with the far-right fundamentalist Catholic institution Opus Dei, which grew strongly and flourished during the thirty-six years of the Francisco Franco (1892-1975) dictatorship in Spain.

I clearly remember what the award-winning journalist and columnist Heidi Schlumpf wrote in America magazine on November 7, 2025: “That the United States now seems to be exploding with Catholic fundamentalist movements is more than a little concerning, not just for the Church but for the country, if Catholics join forces with groups and individuals advocating for Christian nationalism. It is clear that Catholic fundamentalism, with its inherent militancy, is a serious threat, especially at a time of rising ideological violence. The solutions to these broader societal issues are not simple, but understanding the religious roots and connections is critical.”

Critical times. But I am not pessimistic. We need to deal constructively with Catholic fundamentalism by fostering dialogue over hostile debate, by focusing on charity, and by providing a more nuanced understanding of Catholic tradition.

We need to promote good education and encourage critical thinking, helping people understand that fear of questions and change can lead to rigidity, while true faith often involves grappling with complex questions.

• Jack