Pope Leo XIV has made a final appeal to a breakaway traditionalist Catholic group, urging them to abandon plans to consecrate new bishops without papal consent. The pontiff described the planned action by the Society of St. Pius X (SSPX) as a schismatic act and a "sin of extreme gravity."

In a letter to the Rev. Davide Pagliarani, the superior of the SSPX, Pope Leo XIV pleaded, "I ask you with all my heart: please turn back!" The letter was issued just before the society's planned consecration of four new bishops at its seminary in Econe, Switzerland. According to church law, such consecrations performed without papal approval constitute a schismatic act, signifying a deliberate break from the unity of the Catholic Church, and carry automatic excommunication for those involved.

Marc-André Mabillard, media manager for the SSPX, expressed "great sadness to not be understood by our leader," but stated, "We are changing absolutely nothing in our plans." When questioned about the prospect of excommunication, Mabillard acknowledged that while it would cause immense pain, the group believes "the good we seek is greater than the pain that will be inflicted upon us."

This situation presents the first significant crisis for Pope Leo XIV, who has prioritized church unity since his pontificate began. He has particularly focused on mending relations with traditionalist Catholics who favor the old Latin Mass, a tension that reportedly increased during Pope Francis's papacy.

The SSPX was established in opposition to the modernizing reforms introduced by the Second Vatican Council in the 1960s. These reforms included significant changes to the Church's interreligious relations, its engagement with the laity, and the allowance of Mass to be celebrated in vernacular languages instead of Latin.

Members of the SSPX observe the ancient Latin Mass and contend that the contemporary Church is permeated by heresies and errors. They maintain that only the SSPX preserves the true faith of Christ and have invoked a "state of necessity" to justify their planned consecrations, citing the need to minister to their followers.

In 1988, the SSPX's founder, Archbishop Marcel Lefebvre, consecrated four bishops without papal authorization, an act that led to his and the four bishops' excommunication by the Vatican. The group currently lacks official standing within the Church.

The Vatican lifted these original excommunications in 2009 as part of an effort to reintegrate the group. However, the Vatican has warned that a similar outcome awaits the new bishops if the consecrations proceed as planned.

In his letter, Pope Leo XIV reiterated the Vatican's openness to dialogue and cautioned that the consecrations would be detrimental to the SSPX faithful. He wrote, "I urge you to consider carefully the spiritual good of the faithful, because the schismatic act you are about to undertake would deprive them of the licit, and in some cases, even valid reception of the sacraments."

Despite the 1988 schismatic act, the SSPX has continued to expand. It now represents a challenge to the Holy See as a parallel, strictly pre-Vatican II Catholic entity. According to SSPX statistics, the group comprises two bishops, 751 priests, 264 seminarians, 145 religious brothers, 88 oblates, and 250 religious sisters from 50 nationalities.