When San Diego Bishop Robert McElroy receives his prestigious red hat at the Vatican on Saturday, he will bring to the College of Cardinals a fervent devotion to Pope Francis that has frequently pitted him against the conservative majority of the United States Conference of Catholic Bishops.

McElroy, 68, is the only American among the 21 clerics being installed as cardinals at St. Peter’s Basilica by Francis. He was chosen over a number of higher-ranking American archbishops, including two from his own state: outspoken conservative Salvatore Cordileone of San Francisco and José Gomez of Los Angeles, president of the United States Conference of Catholic Bishops.

McElroy is one of the few American bishops who has questioned why the conference insists on naming abortion as its “preeminent” priority. Echoing the pope’s concerns, he has questioned why issues such as poverty, immigration, and climate change are not given more attention.

McElroy was described as “one of the foremost articulators in the United States not only of Pope Francis’ vision but also of the vision of the Second Vatican Council and, more fundamentally, the vision of the Gospel” by Rev. James Martin, editor-at-large of the Jesuit magazine America.

McElroy “often speaks from the ideological margins,” according to Chad Pecknold, a theology professor at The Catholic University of America who has frequently criticized Francis, and thus would be seen as an appropriate candidate for cardinal during Francis’ papacy. Among his notable positions, McElroy was one of a small group of U.S. bishops who opposed the campaign to bar Catholic politicians who support abortion rights from Communion.

Cordileone, on the other hand, announced earlier this year that he would no longer allow House Speaker Nancy Pelosi to receive Communion due to her support for abortion rights.

He attended St. Patrick Seminary in Menlo Park, California, and earned a theology degree from the Jesuit School of Theology in Berkeley in 1985. The following year, he earned a doctorate in moral theology from the Gregorian University in Rome, followed by a doctorate in political science from Stanford.

He was ordained in 1980 and assigned to the Archdiocese of San Francisco, where he served in a parish before becoming Archbishop John Quinn’s personal secretary. Other parish assignments in California included Redwood City and San Mateo.

In 2010, he was appointed as an auxiliary bishop in San Francisco. Francis was named bishop of San Diego in 2015, early in his pontificate. He has been the president of the California Bishops Conference for the past three years.

Monsignor Stephen Doktorczyk, vicar-general of the Diocese of Orange, praised McElroy’s leadership abilities.

McElroy’s elevation, according to Allan Figueroa Deck, a distinguished scholar of pastoral theology at Loyola Marymount University, represents a “clear message” from the pope about the direction the church should take.

McElroy “understands and takes seriously what Pope Francis means by ‘epochal change,’ as well as the challenge of finding better models, a more effective and inclusive style for the Church to move forward,” Deck said in an email. “He approaches contentious issues with balance and prudence, such as pastoral care for LGBTQ people and abortion.”

McElroy has been a frequent target of conservative Catholic activist Michael Hichborn of the Lepanto Institute, who, for example, has condemned his strong support for the Association of United States Catholic Priests. The association is a relatively liberal organization whose priorities include increasing the role of women in church leadership and establishing “priestless parishes” that could potentially be overseen by laypeople to address the priest shortage.

Hichborn said in an email that McElroy’s appointment “is a sign of Pope Francis’ desire to marry the Church with the world.” “There is little doubt that McElroy currently serves as a model for the type of priest, bishop, and cardinal Pope Francis wishes for the Church’s future.”

The Diocese of San Diego stretches the entire length of California’s border with Mexico, serving over 1.3 million Catholics in San Diego and Imperial counties. It has 98 parishes, 49 elementary and secondary schools, and various social service and family support organizations through Catholic Charities of the Diocese of San Diego.