Wester became archbishop of the Archdiocese of Santa Fe in 2015 after serving as bishop of Salt Lake City, and before that, auxiliary bishop of San Francisco. His Jan. 11, 2022, pastoral letter called, "Living in the Light of Christ's Peace: A Conversation Toward Nuclear Disarmament" is the first official document in U.S. church history calling for the abolition of nuclear weapons. Wester spoke about his first visit to Hiroshima a few years ago, and returning home to Santa Fe and seeing the place where the scientists worked on the actual Hiroshima bomb. "I felt the Lord calling me to do something about multi-lateral verifiable nuclear disarmament," he said. We're not just commemorating the past but trying to preserve the future."