Those in power virtually never give it up willingly. In Congress or on the local school board, at the office or on a coaching staff, who do you know who's done that?Pope Benedict XVI, that's who, and before we skip straight to guessing who will succeed him on the Chair of Peter, let's acknowledge how brave and extraordinary a thing he's done in knowing when to say when. We should all be so wise.Funny that a man so many associate with the Middle Ages will go down in history for modernizing -- but he will. That's because his retirement bows not only to the reality that we live longer now, but to the fact that for all the incense and candlelight surrounding the papacy, it is, among other things, a job, with real-world obligations that one either can or cannot fulfill.Why the former Joseph Ratzinger is bowing out at 85 is what everyone wants to know, but to my friends who wonder whether the Vatican is cannily trying to shift the narrative from sex abuse and Cardinal Roger Mahony to self-sacrifice and Holy Week, I'll just say I never suspect Rome of being PR savvy.In fact, Benedict's motivations in stepping down aren't a mystery at all: He never exactly hankered for the job, and, according to someone with direct knowledge of his thinking, in the years since ascending to the Chair of Peter in 2005, he has on several occasions voiced doubts about whether he should have accepted it.Benedict has always said he would step down if he felt he could no longer do his best for the world's billion Catholics, and we shouldn't forget that few had a better view than he did of John Paul II's painful final years, when the vacuum left by the pope's infirmity raised all kinds of uncomfortable questions about who was really in charge at the Vatican.Benedict is an academic. For the quarter-century before he became pope, he was the pope's theologian, and it's important to remember that for two reasons: First, because he is so cerebral, the mental slowing-down that he's referred to is a problem he would take extra seriously. And it's hard to imagine him dreading a return to a life with much more time for reading and writing.That is not to say he's leaving because the job has gotten too hard. I don't believe he'd allow himself that kind of an out. He's been explicit that his personal comfort shouldn't and wouldn't be a factor in any such decision to step down, once saying, "When the danger is great, one must not run away."My friend and colleague E.J. Dionne correctly notes that Benedict has neither been as conservative as conservatives would have liked nor as conservative as some of the rest of us feared when the bells rang in St. Peter's Square eight years ago -- and in some ways, yes, he sounds like a good American progressive, writing in a December op-ed that "Christians fight poverty out of a recognition of the supreme dignity of every human being, created in God's image and destined for eternal life."But when we assess his papacy, we really can't do it in strictly secular or conventionally political terms. We need to bring a little realism to the exercise, too. I see all these looks back that have Benedict down as a known opponent of same-sex marriage, abortion and women's ordination, and I think, well, yes, but that's like saying such and such rabbi is known for not eating pork. It would have been true of anyone chosen in the papal conclave of 2005, and it will be true of anyone chosen in the papal conclave of 2013.Melinda Henneberger is a Washington Post political writer and anchors the blog She the People.