The question of whether or not hell is empty is an old, but it is getting new life because of a forthcoming book by an evangelical preacher who holds the universalist position. Father Robert Barron who teaches theology at Mundelein recaps the history of the debate and sides with the position of the great Swiss theologian Hans Urs von Balthasar, namely, that we have reason to hope that hell is empty.
This article recalled an event in the 1990s, I can't remember exactly when. The Holy Father, Pope John Paul II, made a reference to Balthasar's teaching in this regard at one of his Wednesday General Audiences. It happened to be during the summertime when Cardinal Raztinger was on holiday. The Italian press had a field day with headlines that said, as I recall, "While Ratzinger is away, Pope becomes heretic." But, Balthasar catches something important, and it is the thing that drove Pope John Paul II in his finer moments. Of course we can't know if hell is empty, but in contemplating the power of the Cross, we must hope that it is so.