When is marriage consent invalid?

​A declaration of nullity, sometimes called an annulment, is a decision issued by the Catholic Church, through the marriage tribunal, that a marriage is invalid because something essential was absent at the time of the exchange of consent. A petition for the tribunal to investigate a marriage is a petition to examine whether the marriage was invalid from the very beginning, meaning from the day of the wedding.

Below you will find a list of the principal reasons (called grounds) for which a marriage can be declared invalid, based on Church law. A tribunal can investigate one or more of these grounds, on the part of the petitioner (who is seeking the annulment), respondent (the divorced spouse), or both. The judicial vicar determines the ground in a marriage case, in consultation with the defender of the bond.

1 Total simulation: at the time of the wedding, one or both parties did not intend to enter marriage at all and excluded all the goods of marriage (ex. marrying for immigration purposes).

2 Partial simulation: at the time of the wedding, one or both of the parties positively excluded one or several of the goods of marriage (children, fidelity, permanence, good of the spouse, and/or sacramentality).

3. Deceit: prior to the wedding, one or both of the parties were deceived about an aspect of the other person that was so significant they would not have married that person if they were aware of the fact (ex. a man hides his addiction issues).

4. Error about the nature of marriage: at the time of the wedding, one or both parties actually did not understand the nature of marriage as a permanent and exclusive union between two people, ending only with death, and ordered for the procreation and raising of children (ex. a man is born in a culture where polygamy is predominant and that is his understanding of marriage).

5. Force or fear: at the time of the marriage one or both parties were forced to get married by force or out of fear of some situation (ex. a man will commit suicide if the woman does not marry him).

6. Lack of sufficient use of reason: At the time of the wedding one or both of the parties lacked the necessary use of reason to consent to marriage. This could be because of a temporary (ex. severe intoxication at the time) or permanent (ex. psychological infirmity) condition.

7. Grave lack of due discretion: At the time of the wedding, one or both of the parties were not capable of entering into a marriage and its obligations due to temporary or permanent disturbance.

8. Inability to assume the essential obligations of marriage: At the time of the wedding, one or both of the parties had a psychological infirmity which prevented their assuming of marital obligations.

9. Ignorance about the nature of marriage: At the time of the wedding, one or both of the parties was ignorant about marriage as a permanent partnership between a man and a woman which is ordered toward the procreation of offspring by means of some sexual cooperation​ (ex. someone with an extremely sheltered upbringing).

​10. Error of person: At the time of the wedding, one of the parties thought they were marrying someone else (ex. a twin brother).

11. Error of quality: At the time of the wedding, one of the parties is principally intending to marry someone for a quality they have. The person having the quality is more important than who the person is (ex. a person thinking they are marrying into the nobility).

12. Conditioned consent: At the time of the wedding, one of the parties placed a condition upon their matrimonial consent and either the condition was not fulfilled or it concerned the future.