In his first speech as pope, Benedict XVI declared, “The current Successor assumes as his primary commitment that of working tirelessly towards the reconstitution of the full and visible unity of all Christ’s followers.â€1 Before he took the name Pope Benedict XVI, Joseph Cardinal Ratzinger had already established a name for himself as the “Vatican’s doctrinal watch-dog,†head of the Congregation of the Doctrine of the Faith. In that capacity, Cardinal Ratzinger was the guiding hand in John Paul II’s famous encyclicals, such as Dominus Iesus, which continued to regard the theology of the Reformation as “gravely deficient.†Yet he...