Legislation would ban mifepristone, although its path forward in Congress remains uncertain.

"In his work, Father Fuller has demonstrated a pastoral heart, a theologian's mind, and a worthy steward's deft guiding hand," said Archbishop Paul S. Coakley, president of the USCCB.

“On behalf of my brother bishops, I wish to extend our warmest welcome and our prayerful support to him as he carries out his responsibilities across the United States, and we look forward to working with him.

In a statement, Archbishop Caccia highlights this new role as a “mission at the service of communion and peace."

The group is named for two patrons with causes for canonization underway: Staten Island's Dorothy Day, co-founder of the Catholic Worker Movement, and Sister Thea Bowman.