St John Paul II:

When legislation in favour of the recognition of homosexual unions is proposed for the first time in a legislative assembly, the Catholic law-maker has a moral duty to express his opposition clearly and publicly and to vote against it. To vote in favour of a law so harmful to the common good is gravely immoral (Considerations regarding proposals to give legal recognition to unions between homosexual persons, June 3rd, 2003)

Pope Francis:

Franca Giansoldati, Il Messaggero (Italy): Holiness, good evening. I return back to the topic of the law that is being voted on in the Italian parliament. It is a law that in some ways is about other countries, because other countries have laws about unions among people of the same sex. There is a document from the Congregation for the Doctrine for the Faith from 2003 that dedicates a lot of attention to this, and even more, dedicates a chapter to the position of Catholic parliamentarians in parliament before this question. It says expressly that Catholic parliamentarians must not vote for these laws. Considering that there is much confusion on this, I wanted to ask, first of all, is this document of 2003 still in effect? And what is the position a Catholic parliamentarian must take?

Pope Francis: I do not remember that 2003 document from the Congregation of the Doctrine of the Faith well but every Catholic parliamentarian must vote according their well-formed conscience. I would say just this. I believe it is sufficient because – I say well-formed because it is not the conscience of ‘what seems to me’ (press conference, 18th February, 2016).

St Leo II:

… and also Honorius, who did not purify this apostolic Church by the doctrine of the apostolic tradition, but rather attempted to subvert the immaculate faith by profane treason {Greek version: He allowed the immaculate one to be stained by profane treason} (Letter ‘Regi Regum’ to Constantine IV, c. August 682).