Some have wondered why the Congregation for the Doctrine of the Faith (CDF) issued its "Responses to Some Questions Regarding Certain Aspects of the Doctrine on the Church" at this particular time.

Was the document intended as a kind of shot across the Church's bow, sending an unmistakably clear signal, in tandem with a previous papal document permitting wider usage of the Latin Mass, that the former Cardinal Joseph Ratzinger is finally asserting himself in his new role as Pope Benedict XVI?

Or had there been some major ecumenical provocation requiring the Vatican to draw yet another theological line in the sand, differentiating the Catholic Church from all other churches and ecclesial communities within the Body of Christ, while placing itself well above the rest?

The answer to both questions is "No." To be sure, Cardinal Ratzinger did not change his theological views upon becoming pope. But the Bishop of Rome carries far greater responsibilities for preserving and strengthening the bonds of unity in the Church than does any other ecclesiastical official.

The pope is, by reason of his pastoral office, a bridge-maker, which is what the word "pontiff" (Latin, pontifex) means. He cannot line himself up with one faction in the Church against others. He must be --- to use a well-worn U.S. political slogan--a uniter, not a divider.

That is why he met with his long-time critic, Father Hans Küng, for four hours just a few months after the papal election, whose outcome Küng had publicly deplored.

Benedict XVI is not the pope only of the right. He is the pope of all Catholics, whether he agrees with them or not. Each of them, in principle, must be welcome at the papal dinner table. Unfortunately, that was not the case during the previous quarter-century.

Is Benedict nonetheless still conservative on certain controversial issues affecting the life --- but not necessarily the soul --- of the Church? Of course he is, and his broadening of the permission for the Latin Mass, as well as this latest document from the CDF, are ample evidence of that. But he did not approve this document to make that otherwise obvious point.

Second, has there been some ecumenical catalyst that might explain the issuing of this new CDF document on the Church? Here again, the answer is "No." There is no evidence of any recent development within the ecumenical movement that would explain, much less justify, this initiative.

What is the explanation, then? The head of the CDF, Cardinal William Levada, tells us in his accompanying letter to the bishops. This document, he writes, is in response to criticisms of the CDF's previous document, "Dominus Iesus," issued in September, 2000.

It should be noted here that most of those earlier criticisms came from within the Catholic Church itself --- not just from theologians, but from cardinals and bishops as well, including even high-ranking Vatican officials.

Evidently, those in-house criticisms stung. Seven years later (a virtual nanosecond on the Vatican clock), the CDF and the pope who headed the CDF at the time are finally answering their fellow-Catholic critics.

The official commentary that also accompanied this document mentioned explicitly the need to offer "a sure and certain response" to ecclesiological questions that have been raised by "some" contemporary theological research and which the congregation deems "erroneous, or ambiguous,... [and] at variance with traditional Catholic doctrine on the nature of the Church."

The only theologian cited by name is the Brazilian Leonardo Boff, the former Franciscan who ran afoul of the CDF several years ago for, among other things, describing the Church as a dysfunctional family.

The CDF document poses five questions about the Church and then briefly answers each. The first three questions are of particular interest: "Did the Second Vatican Council change the Catholic doctrine on the Church?" The CDF's answer is "No," but without making any of the necessary qualifications.

Second, "What is the meaning of the affirmation that the Church of Christ subsists in the Catholic Church?" This question is linked with the third: "Why was the expression subsists in adopted instead of the simple word is?"

Here the CDF repeats an interpretation given in the past by Cardinal Ratzinger, but which has been challenged not only by theologians and other Catholic scholars, but also by Cardinal Johannes Willebrands, the former head of the Pontifical Council for Promoting Christian Unity, a leading figure at Vatican II, and the runner-up in the conclave of 1978 that elected John Paul II.

The issues embodied in these questions require further analysis. It will be offered in our next column on this important document.

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