When ministers pray before a business meeting, it’s rare that anyone is asked not to show up. Yet that’s exactly what happened recently at a gathering of—of all people—Anglican bishops. I said “of all people” because the Anglican Communion, which includes the Episcopal Church here in the United States, values unity above almost everything else. They express this unity in the celebration of Communion, a rite that sends the message that, no matter how deep the disagreements may be, the participants are still one in Christ. Imagine, then, the surprise felt by the Archbishop of Canterbury, Rowan Williams, when he...