Baldisseri is the Secretary General of the Synod of Bishops and has had a central role in the synod's preparations, and he will help manage the day-to-day progress of the meetings. He has been in charge of the synod's permanent secretariat in Rome since 2013.
During the last synod session in 2015, on the family, Baldisseri came under criticism for attempting to steer the process and content of the discussions and final document. A letter signed by 13 cardinals, including Cardinal DiNardo, was handed to the pope the day the session began complaining about shortcomings in the working document to be discussed, and of attempts to foist an agenda on the bishops before they had begun discussions.
On Oct. 1, Baldisseri publicly criticized Archbishop Chaput for raising concerns about the working document ahead of this month's session. Chaput, who as a member of the synod's ordinary council was involved in the preparation of the instrumentum laboris, published a theological critique of the working document Sept. 21 prepared by an anonymous theologian.
The critique highlighted "a pervasive focus on socio-cultural elements" in the working document "to the exclusion of deeper religious and moral issues." It also said the text relegated the Church's essential teaching function and authority in favor of a passive posture of "listening" and "dialogue."
Baldisseri said he could not understand Chaput's criticisms, or the need to make them publicly. Instead, the cardinal said, concerns should have been raised privately and could have been included in the document "with calm."
Cardinal Sergio da Rocha is the Archbishop of Brasilia. In November of last year, Pope Francis named him as the relator-general of the synod, charged with outlining the synod's themes at the beginning of the session, and summarizing the contributions of members throughout the synod's progress. He will also play a key role in drafting the text of the synod's final document which will be put to members for a vote.
Cardinal da Rocha has played an active role in public life in his native Brazil, chairing a debate between the country's presidential candidates, and publicly condemning the legalization of abortion in response to the Zika virus outbreak. Da Roche was also a member of the planning committee for the 2015 synod on the family.
Another potentially crucial figure at this month's session will be Cardinal Wilfred Napier Fox, Archbishop of Durban.
Cardinal Napier was also an active participant in the 2014-2015 sessions, where he played a vocal role in opposing what were seen by many as attempts to push through plans to admit the divorced and civilly remarried to Communion over the majority-consensus of the synod fathers.
During the last synod, Pope Francis asked Napier to join the group charged with drafting the synod's relatio, or final document, citing concerns that the Churches in Africa and Oceania were under-represented.
During the drafting meetings, Napier recalled that he objected to the inclusion of language about same-sex couples in the section on marriage, noting that the Church does not recognize such unions to be marriages at all, and that the proposed text undermined efforts by bishops in African countries to oppose the recognition of same-sex unions as marriage.
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Despite his opposition, he said, the drafting committee "just carried on discussing how the proposition should be phrased in Italian." According to an account given by Napier, the drafting committee, led by Cardinal Baldisseri, continued to ignore his objections, prompting an angry intervention in support of him by Washington archbishop, Cardinal Donald Wuerl.
As an outspoken defender of the Church's teaching on life issues and a frequent presence on Twitter, and given his previous criticisms of the synod process being overly managed, many are looking to Cardinal Napier as a potential voice for synod members, and a force for "fair play" in how the final document is drafted.
Another bishop-attendee predicted to play an influential role is Archbishop Stanisław Gądecki of Poznan, president of the Polish bishops' conference. Gądecki has shown himself to be an adept leader of the bishops of one of Europe's most conservative, and sometimes combative episcopal conferences.
During a period in which European countries have struggled to form a common approach to the issues of increased political integration and the migrant crisis, which still dominate large parts of political debate, Gądecki authored a document contrasting the "dangers of nationalism" with the "beauties of patriotism."
Similarly, the pastoral guidelines issued by the Polish bishops' conference on the implementation of Amoris laetitia were widely seen as a thoughtful via media. Emphasizing Pope Francis' priorities like better and longer marriage formation for couples, before and after the wedding, the document stressed the need for pastoral accompaniment for couples in irregular unions, while underscoring the Church's discipline with regards to reception of Communion.
Often seen as an agent of compromise, but unflinching on matters of doctrine, Gądecki could well emerge during the synod as a constructive force in reconciling those looking for a change of pastoral tone with others concerned with protecting the integrity of the Church's teaching and discipline.