Is a Synod binding? Is it magisterial and authoritative?

What is a synod?

A synod is an gathering of bishops to study a particular topic. Synods are ancient, but in 1965 a permanent body was formed by St. Paul VI to advise the pope. The bishops who participate are appointed by bishops conferences, by the worldwide association of women religious (IUSG), or the Pope. These bishops listen to experts in the topic, or those affected by the topic. They discuss then vote on proposals ("propositiones"). The output of the synod is a document addressed to the Pope, who may issue a "post-synod apostolic exhortation" that would form part of the magisterial teachings of the Church.

Resistance against the Synod process

There is concern that recent synods are being used as excuses to liberalize the Church. The 2014 synod on the Family had a swirl of liberal voices going into it and 2018 synod on the youth, had a conspicuous lack of representation from young traditionally minded Catholics.

We agree the Church is in crisis, and that the faithful should meet, plan, pray, storm the heavens, and use modern media to protect the Church. However, we have concerns about attempts to distance the historical Church from the contemporary Church and Magisterium. This puts one at risk of a pseudo heresy which Catholic apologist Dave Armstrong describes as “Reactionary” characterized by the belief that there are serious faults with the documents of Vatican II, the Nous Ordo mass, and popes since the council. Reactionaries appear to adhere to the false belief that the documents that result from a formal magisterial process are not protected and inspired by the Holy Spirit. We think that is a very slippery slope. There is immediate division, even among very faithful people who have a deep love of the Church. Unity is IMPOSSIBLE unless we trust the magisterial teachings and the authority of the output of magisterial gatherings such as Vatican II, formal encyclicals, and post-synod apostolic exhortations, regardless of the bad actors and false statements that went into the process of making those documents. We have to be careful not to drift into the errors of protestantism, which was born in a time of mediocre or poor popes. There were over 260 factions by the time Martin Luther died. The Lord has made a promise to protect the Magisterium from error.

Is the Pope's exortation in response to a synod magisterial and authoritative?

Yes it is, because Pope Francis formally stated that in Episcopalis Communio (Episcopal Communion). Ed Pentin writes that the Pope asserted his authority and cited continuity.

Paul VI foresaw the body [synods] as subject to change “Like every institution,” Paul wrote, “it can be more perfected with the passing of time”.

He highlights the changes in canon law in 1983 and Benedict XVI’s 2006 Ordo Synodi Episcoporum, which among other changes created a general secretariat of the Synod of Bishops.

He also cites Pope St. John Paul II, who suggested the “instrument” of the Synod of Bishops could be “further improved.” ...

Francis says he believes a work of renewal must include more “dialogue and collaboration” between episcopates and the Bishop of Rome. The bishop, he explains, is both “teacher and disciple,” made possible when, helped by the Holy Spirit, he “listens to the voice of Christ speaking through the entire People of God, making them ‘infallible in belief.’

The Pope closes the document by stressing the “full, supreme and universal power” of the Bishop of Rome, which he “can always exercise freely,” but “always united in communion with the other bishops and with the whole Church.” (source)

God has given him the authority to do this.

What about the infamous footnote in Amoris Laetitia?

Here's the quote

351 In certain cases, this can include the help of the sacraments. Hence, “I want to remind priests that the confessional must not be a torture chamber, but rather an encounter with the Lord’s mercy” (Apostolic Exhortation Evangelii Gaudium [24 November 2013], 44: AAS 105 [2013], 1038). I would also point out that the Eucharist “is not a prize for the perfect, but a powerful medicine and nourishment for the weak” (ibid., 47: 1039).

In our opinion it is confusing, unfortunate, divisive, and smells of a liberal agenda. But it has not definitively said that there are instances when it is appropriate to give communion to divorced Catholics who are living with someone new. While it is probable that this is the way Pope Francis intended it, it is not the way he wrote it. Even the Dubia Cardinals asked the Pope to clarify it, instead of issuing a formal correction. They did not issue a formal correction because the document does not contain a formal pronouncement of a change in the moral teaching.

We have every confidence that God will protect the Magisterium from formal error on faith and morals.

Is the final document of a synod magisterial?

The final document of an synod is the opinion of the participating bishops and is not magisterial unless the Pope explicitly says it is. The Pope has asked Catholic to read the final document of the Amazon synod, but he didn't say it's magisterial. February 12, 2020, Vatican spokesman Matteo Bruni said: “The apostolic exhortation [Querida Amazonia] is magisterium. The final document [of the synod] is not magisterium.”

God is the Master Artist and the Church is his creation

A master chef, composer, perfumer, poet, or author chooses disparate ingredients that are sweet, bitter, pungent to create a beautiful work of art. Similarly, God the Father, Jesus and the Holy Spirit guide the Church when new documents are created under the authority of the Pope. There are sometimes very bitter inputs into these documents, but the output is of God, and therefore good and right.