Annulment question

[Stubborn]

Remember when Bergo flipped this on its head?

Pope Francis said Thursday that many sacramental marriages today are not valid, because couples do not enter into them with a proper understanding of permanence and commitment.

While he initially said in unscripted comments that "the great majority of our sacramental marriages are null," he later approved a revision of these remarks.

When the Vatican released its official transcript of the encounter the following day, they had changed the comment to say that "a portion of our sacramental marriages are null."

I've said it before - I do not want to be me at my Particular Judgement, but I'd rather be me than him. Lord have mercy!

[Gardener]

completely secular marriage

There is no such thing as a "secular marriage". Marriage is a sacrament. If there is no sacrament, there is no marriage. If there is no marriage, there is nothing to annul.

A man and a woman who pretend they are married and live that way, when they in fact are not married, are living in sin. They can separate whenever one of them fancies. There is nothing holding them together, because sin is not a force that unites, but a force that divides and destroys.

But, if they honestly repent and confess their sins, assuming they are baptized and confirmed, they can receive the sacrament of marriage (with each other, or find someone else), and this union, which is so pleasing to God, cannot be broken by any man, and lasts until death separates them.

This was addressed in Q5 which you quoted here (I've italicized where it's showing a natural marriage (which is the proper term) and added underlining where it's comparing with Christian Marriage, aka a Sacrament:

From the Catechism of St. Pius X:

Nature of the Sacrament of Matrimony

1 Q. What is the sacrament of Matrimony?
A. Matrimony is a sacrament, instituted by our Lord Jesus Christ, which creates a holy and indissoluble union between a man and woman, and gives them grace to love one another holily and to bring up their children as Christians.

2 Q. By whom was Matrimony instituted?
A. Matrimony was instituted by God Himself in the Garden of Paradise, and was raised to the dignity of a sacrament by Jesus Christ in the New Law.

3 Q. Has the sacrament of Matrimony any special signification?
A. The sacrament of Matrimony signifies the indissoluble union of Jesus Christ with the Church, His Spouse, and our holy Mother.

4 Q. Why do we say that the bond of marriage is indissoluble?
A. We say that the bond of marriage is indissoluble or that it cannot be dissolved except by the death of either husband or wife, because God so ordained from the beginning and so Jesus Christ our Lord solemnly proclaimed.

5 Q. Can the contract be separated from the sacrament in Christian marriage?
A. No, in marriage among Christians the contract cannot be separated from the sacrament, because, for Christians, marriage is nothing else than the natural contract itself, raised by Jesus Christ to the dignity of a sacrament.

6 Q. Among Christians, then, there can be no true marriage that is not a sacrament?
A. Among Christians there can be no true marriage that is not a sacrament.

7 Q. What effects does the sacrament of Matrimony produce?
A. The sacrament of matrimony: (1) Gives an increase of sanctifying grace; (2) Gives a special grace for the faithful discharge of all the duties of the married state.

...

23 Q. What is a civil marriage?
A. It is nothing but a mere formality prescribed by the [civil] law to give and insure the civil effects of the marriage to the spouses and their children.

24 Q. Is it sufficient for a Christian to get only the civil marriage or contract?
A. For a Christian, it is not sufficient to get only the civil contract, because it is not a sacrament, and therefore not a true marriage.

25 Q. In what condition would the spouses be who would live together united only by a civil marriage?
A. Spouses who would live together united by only a civil marriage would be in an habitual state of mortal sin, and their union would always be illegitimate in the sight of God and of the Church.

26 Q. Should we also get the civil marriage?
A. We should perform the civil marriage, because, though it is not a sacrament, it provides the spouses and their children with the civil effects of conjugal society; for this reason, the ecclesiastical authority as a general rule allows the religious marriage only after the formalities prescribed by the civil authorities have been accomplished.

Natural:
Marriage

Supernatural:
Marriage (as raised by Christ)

Only 1 is a Sacrament, but natural marriage is still marriage. Only when one is a Christian can it be said one cannot be married if lacking the Sacrament. We are simply unable, one might even say ontologically unable due to our Baptism, to contract natural marriage.

One can see a parallel with priests who, because they are ontologically changed in ordination, cannot contract Sacramental Marriage. Why? Because virginity/celibacy is a more valuable and important vow they take before their superior and God. They simply cannot go "down" to a Sacrament of lesser dignity, though dignified nonetheless.

[KreKre]

Thank you for the excellent explanation, @Gardener . I had not considered the concept of marriage as it applies to non-Christians, and incorrectly assumed that the same rules apply.