Ever since the sexual-abuse crisis erupted in the U.S. Roman Catholic Church in the mid-1980s, with allegations of child molestation by priests, commentators have regularly compared the problems faced by the Church to those it faced in Europe at the start of the sixteenth century, on the eve of the Protestant Reformation—problems that included sexual laxity and financial malfeasance among the clergy, and clerical contempt for the interests of the laity. Calls for change have become increasingly urgent since January, when revelations of widespread sexual misconduct and grossly negligent responses to it emerged prominently in the Boston archdiocese. Similar, if...