As far as I can tell, popes have always been able to resign if they wanted. From the later Middle Ages onward, none did so; till now. Why this should be so takes only a moment’s thought.
Up till the Reformation and beyond, popes ruled in a world of absolute power, in which rulers were forever calibrating their magnificence and heft against each other. The popes saw themselves as supreme overlords who like Gregory VII could summon emperors or, like Julius II appear on the battlefield or remodel Rome. Who would ever give up such power?
Pius IX and his five immediate successors let the papacy curdle into pietistic irrelevance and concealed its waning power and influence beneath a phaoronic gloss of confidence. When Harold Macmillan met Pius XII in 1944 he described him as at once tremendous and pathetic. None of this sextet would have considered resignation for a moment. So we have grown accustomed to the idea that, on principle, popes go on till death and die in office. Now we know they don’t have to.
Now we live in a world where executives and heads of state and government lose their jobs under pressure. The system cannot afford passengers, or so we are told. Thus it seems only right that an 85-year-old chairman of the board, with a pacemaker and accumulating infirmities, should chuck it in.
Benedict XVI has not been a good pope, but nothing becomes him more than his willingness to stand aside a let a younger, fitter, bolder man take his place and brace the church against its multiplying challenges. Who will it be?

