Pope Francis has expelled Theodore E. McCarrick, a former cardinal and archbishop of Washington, from the priesthood, after an expedited canonical process that found him guilty of sexually abusing minors and adult seminarians over decades, the Vatican said on Saturday.

“The Holy Father has recognised the definitive nature of this decision made in accord with law” — making it final — the Vatican said of the sentence handed down by its doctrinal watchdog.

It appears to be the first time that a cardinal or bishop in the US has been defrocked, or laicised, from the Roman Catholic Church, and the first time any cardinal has been laicised for sexual abuse.

Laicisation, which strips a person of all priestly identity, also revokes church-sponsored resources like housing and financial benefits.

While the Vatican has laicised hundreds of priests for sexual abuse of minors, few of the church’s leaders have faced severe discipline. The move to defrock McCarrick is “almost revolutionary”, said Kurt Martens, a professor of canon law at the Catholic University of America.

“Now you will see that bishops are also treated like their priests,” Martens said in a phone interview. “Bishops and former cardinals are no longer immune to punishment. The reverence that was shown in the past to bishops no longer applies.”

McCarrick, now 88, was accused of sexually abusing three minors and harassing adult seminarians and priests. A New York Times investigation last summer detailed settlements paid to men who had complained of abuse when McCarrick was a bishop in New Jersey in the 1980s, and revealed that some church leaders had long known of the accusations.

Francis accepted McCarrick’s resignation from the College of Cardinals in July and suspended him from all priestly duties. He was first removed from ministry in June, after a church panel substantiated a claim that he had abused an altar boy almost 50 years ago.

McCarrick was long a prominent Catholic voice on international and public policy issues, and a champion for progressive Catholics active in social justice causes.

The move is the most serious sign to date that Pope Francis is addressing the clerical sex abuse crisis in the US. In October, the pope laicised two retired Chilean bishops accused of sexually abusing minors.

In a statement on Saturday, the Vatican said that the prelate had been dismissed from a clerical state after he was tried and found guilty of several crimes: “solicitation in the Sacrament of Confession, and sins against the Sixth Commandment with minors and with adults, with the aggravating factor of the abuse of power.”

One of McCarrick’s accusers has said that when he was a boy, the then-priest touched his genitals during confession.

McCarrick was notified Friday of the January 11 ruling and had appealed. On Wednesday, the Vatican’s doctrinal watchdog, the Congregation for the Doctrine of the Faith, rejected his appeal.

On Saturday, the Vatican spokesman, Alessandro Gisotti, said the congregation had extended McCarrick a penal process in which “all his rights were respected” and that his “lawyers played an active role in the course of some of the interrogations”.