The last time Lucien Greaves got into this much trouble over a photograph, he had his genitals out. In July 2013, Greaves gained nationwide media attention for resting his scrotum on the gravestone of the Reverend Fred Phelps’s mother—a stunt designed to protest the homophobia of the Westboro Baptist Church, an ultra-conservative group that was then regularly featured on the news. Greaves was trading offense for offense. Phelps’s church had a habit of protesting soldiers’ funerals with placards telling gay people that they were going to hell. So Greaves claimed to have performed a “Pink Mass” that turned the mother of Westboro’s patriarch gay in the afterlife. The stunt was typical of Greaves and of the Satanic Temple, or TST, the group that he had co-founded months earlier. The Temple uses Greaves’s talent for the profane and the outrageous, along with strategic lawsuits, to target Christianity’s special status in American public life. Think of it as the ACLU with pentagrams. Greaves himself is a striking figure, charismatic and droll, pale and slender, usually dressed in …