Roman Catholicism is rich and vibrant. But someone has to keep the Church honest... In short, the Reformation seemed to us to be “back there,” and I felt no need to defend Protestantism because it seldom occurred to me that being a Protestant was all that important or interesting. The antagonism of the past simply seemed no longer relevant. It was the ’60s; we were attracted to theology as part of a general attempt to make the world better. Protestant-Catholic sectarianism didn’t feel current... In 1974, I interviewed for my job teaching theology at Notre Dame. Things were going well until a professor on the hiring committee asked what I wanted to teach graduate students. I said I would like to teach a seminar on Aristotle and Aquinas. The response was immediate: “Why would you, a Protestant, want to teach a course on a Catholic thinker?” Christianity did not begin in the 15th century, I replied. I argued that Aquinas was not a possession of Roman Catholics but a resource for all Christians, whether Protestant or Catholic... It was a small moment, but in that exchange, I began to understand that we were in a new day: Five hundred years after its inception, we are witnessing the end of the Reformation. The very name “Protestant” suggests a protest movement aimed at the reform of a church that now bears the name of Roman Catholicism. But the reality is that the Reformation worked. Most of the reforms Protestants wanted Catholics to make have been made.. Over time, historians have helped us see that there was no one thing the Reformation was about, but that if there was a single characteristic at its heart, it was the recovery of the centrality of Christ for making sense of why Christians are not at home in this world... That the Reformation has been a success, however, has put Protestantism in a crisis. Winning is dangerous — what do you do next?.. The result is denominationalism in which each Protestant church tries to be just different enough from other Protestant churches to attract an increasingly diminishing market share... Yet, perhaps tellingly, a number of my Protestant graduate students have become Roman Catholics over the years. (So many crossed the Tiber that my colleagues joked I was an agent for Opus Dei.) They convert because Catholicism is an intellectually rich theological tradition better able to negotiate the acids of our culture. They also take seriously that Roman Catholicism represents a commitment to Christian unity, not only toward non-Catholic Christians but between the poor and those who are not poor... But I also remain a Protestant because I have the conviction that the ongoing change that the church needs means some of us must be Protestant to keep Catholics honest about their claim to the title of the one true Catholic Church. The Reformation may be coming to an end, but reform in the church is never-ending, requiring some to stand outside looking in.