One wonders, therefore, why he consented to appear in a joint press conference with the new Roman Catholic Archbishop of Westminster, Vincent Nichols, to greet the news.

Archbishop Williams subsequently met briefly with Pope Benedict XVI in November–a meeting that had been scheduled prior to the announcement of the initiative–at which meeting the subject of the initiative reportedly did arise.

The conversation between the two religious leaders was described as frank, but cordial. Indeed, so cordial was the meeting that the pope gifted the archbishop of Canterbury with a pectoral cross -- an implicit, even if unintended, recognition that Rowan Williams possesses valid episcopal orders.

The gesture was reminiscent of Pope John Paul II's gift in 1996 of a gold pectoral cross to Rowan Williams's predecessor, Archbishop George Carey (now Lord Carey), on the occasion of the 1400th anniversary of Pope Gregory the Great's sending of a group of monks, under the leadership of Augustine of Canterbury, to re-Christianize Briton.

We can refer to these as "mixed signals," since the official stance of the Catholic church toward Anglican Orders remains that of Pope Leo XIII, given in his famous papal bull Apostolicae curae ("Of apostolic concern") 100 years earlier, namely, that Anglican ordinations to the priesthood, and especially to the episcopate, are "absolutely null and utterly void."

Indeed, in a commentary issued in 1998 by then-Cardinal Joseph Ratzinger, head of the Vatican's Congregation for the Doctrine of the Faith, Leo XIII's decree was cited as an example of a "definitive" pronouncement, closely connected with revelation itself.

Was John Paul II implicitly denying that century's-old teaching? Was Benedict XVI doing the same?

As we look more closely at the Apostolic Constitution Anglicorum coetibus ("On groups of Anglicans") and the accompanying norms released by the Congregation for the Doctrine of the Faith, one is struck not only by its canonical and pastoral complexity, but also by its ecumenical potential.

If the Catholic church is prepared to foster reunion with a small portion of the Anglican Communion with such a bold initiative, why could it not do the same for other churches and ecclesial communities in the Body of Christ?

Why could not all churches and ecclesial communities currently separated from full communion with the Catholic church enter into that communion without sacrificing their own distinctive traditions -- liturgical, sacramental, spiritual, theological and canonical?

In that case, we could have a Presbyterian community in full communion with the Catholic church without sacrificing or jettisoning any of their most cherished traditions. The same might apply to Lutherans, Methodists, and so on.

To be sure, these arrangements, like the recent Vatican outreach to certain Anglicans, would be complicated and require a lot of ecclesiastical fine-tuning over many years. But that could very well be the harbinger of ecumenical things to come.

What is also clear from the Apostolic Constitution is that the Vatican was not somehow "poaching" on Anglican territory. The very first paragraph points out that groups of Anglicans have "repeatedly and insistently" petitioned to be received into full Catholic communion "individually as well as corporately."

Moreover, since 1980 there has existed a Pastoral Provision, also known as the Anglican Use, whereby Anglican priests (inappropriately called "ministers" in this latest Vatican document) who wish to enter into full communion with the Catholic church and who are eligible for ordination to the Catholic priesthood may be dispensed from the discipline of clerical celibacy.

The Apostolic Constitution provides the ecclesiastical means for full communion that is corporate, and in that sense seems to go beyond the terms of the Pastoral Provision.

Finally, to settle the question of whether former Catholic priests who subsequently became Anglicans might exercise their priesthood in the new Anglican Ordinariates, the Complimentary Norms definitively answer that in the negative (see article 6, §2).

There are many more items that one might address in the Apostolic Constitution and Compli-mentary Norms, but readers should study those documents for themselves. They are available on the Vatican Web site and published in Origins (vol. 39, no. 24, 11/19/09).

----Fr. Richard P. McBrien is the Crowley-O'Brien Professor of Theology at the University of Notre Dame