The Vatican is striking back at conservative critics of Pope Francis' landmark document on family life, ratcheting up its defense of the pope with new vigor as bishops begin implementing the document around the world.

The Vatican newspaper L'Osservatore Romano on Wednesday carried a lengthy essay by an Italian Catholic historian insisting that Francis' "The Joy of Love" was absolutely in line with his predecessors and church doctrine on the thorny issue of whether divorced and civilly remarried Catholics can receive Communion.

Earlier this month, the Vatican-approved magazine La Civilta Cattolica ran an interview with Cardinal Christoph Schoenborn in which the Vienna archbishop pointedly rejected conservative claims that Francis' work didn't count as an authoritative teaching document.

Both articles upped the ante in the increasingly divisive theological and ideological battle sparked by "The Joy of Love," and were published on the eve of Francis' trip to Poland, where the Jesuit pope will symbolically deliver the document to the deeply conservative Polish church at a youth rally next week.

When it was released in April, "The Joy of Love" immediately sparked controversy because it opened the door to civilly remarried Catholics receiving Communion. Church teaching holds that unless these divorced and remarried Catholics obtain an annulment — a church decree that their first marriage was invalid — they cannot receive the sacrament, since they are seen as committing adultery.

Francis didn't create a church-wide pass for these Catholics, but suggested — in vague terms and strategically placed footnotes — that bishops and priests could do so on a case-by-case basis after accompanying them on a spiritual journey of discernment.

The conservative criticism was swift.

American Cardinal Raymond Burke, a figurehead for archconservatives who was removed by Francis as the head of the Vatican's supreme court, insisted that the document wasn't part of the church's teaching magisterium but rather was a personal reflection on meetings of bishops about family matters.

"The personal, that is, non-magisterial, nature of the document is also evident in the fact that the references cited are principally the final report of the 2015 session of the Synod of Bishops and the addresses and homilies of Pope Francis himself," Burke wrote in the National Catholic Register.

Schoenborn rejected Burke's claim in his interview with Civilta Cattolica.

The document, Schoenborn said, "is an act of the magisterium that makes the teaching of the church present and relevant today."

Italian Cardinal Carlo Caffarra, another leading conservative, has criticized the document as vague and confusing, and denied that it opened the door to Communion, since doing so would contradict previous church teaching on the indissolubility of marriage.

Francis' own doctrine czar, German Cardinal Gerhard Mueller, concurred with Caffarra, saying the pope would have been more clear if he had intended such an opening. Mueller argued in a May 4 speech in Spain that decisions about whether someone can receive the sacraments cannot be arrived at purely in the realm of individual, private discernment.

"A privatization of the sacramental economy would certainly not be Catholic," he said.

In Wednesday's Osservatore Romano, Italian historian and politician Rocco Buttiglione said the church has always taught that there can be cases in which the faithful might not believe themselves to be in a state of mortal sin, or might not be fully responsible for it, which can mitigate their culpability.

"The path that the pope proposes to divorced and remarried is exactly the same that the church proposes to all sinners: Go to confession, and your confessor, after evaluating all the circumstances, will decide whether to absolve you and admit you to the Eucharist or not," he wrote.

Buttiglione's argument, featured on the front page, marked a shift in the Vatican's defense of Francis' document, confronting the criticisms head-on rather than just praising the pope's text.

The initiative could signal a more concerted campaign by the Vatican to ensure that the "The Joy of Love" is interpreted as Francis intended. Already, conservative Philadelphia Archbishop Charles Chaput has said that divorced and civilly remarried Catholics can only receive Communion in his archdiocese if they abstain from sex and live as "brother and sister."

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