Q. Are faithful Catholics committing a sin by going to a nonpracticing Catholic’s wedding not in the Catholic Church? Also, if they are practicing Catholics, but not getting married in the Catholic Church, are we allowed to attend? I have received different answers from different priests; it is so confusing. — Mary

A. There are two questions here: whether the marriages will be valid (i.e., whether they will come into existence); and whether, if they will not be valid, you may rightly attend the weddings.

Are the Marriages Valid?

The first question concerns validity. A valid marriage is a real marriage. When it’s between baptized Christians, it is a sacrament.

The opposite, an invalid marriage, is not a real marriage. It is a semblance of a marriage. 

There are several things necessary for bringing into existence a valid marriage, related to the couple’s capacity for marriage, to the nature of their consent, and to the proper form according to which they celebrate the marriage. Your question specifically raises doubts about the third. 

For a marriage to be valid, a baptized or otherwise confirmed Catholic is required to contract his or her marriage before an authorized minister of the Church, usually a priest or deacon, and before two witnesses. 

One can receive a dispensation by one’s local bishop from the first requirement. This might take place, for example, if a Catholic, who is marrying a Protestant, desires to marry according to the Protestant form of the other party. In such a case, the Catholic can be freed to be married by a Protestant minister. 

Without a dispensation, a marriage attempted by a Catholic would be invalid.

Regarding the two categories of Catholics you mention — “practicing” and “nonpracticing” Catholics who are not getting married in the Catholic Church — canon law says this: 

“The form … must be observed if at least one of the parties contracting the marriage was baptized in the Catholic Church or received into it” (1117, modified 2009). 

This canon makes clear that the conditions of proper form apply not only to practicing Catholics but also to nonpracticing ones.

Necessity of Proper Form

So why is proper form required for a valid marriage?

In past centuries, the Catholic Church confronted the problem of clandestine marriages. These were situations where a couple would conduct their marriage in secret. Because those marriages needed to be cared for pastorally, including in the difficult case where the couple’s communion broke down, the Church needed a way to verify that the marriages came into existence in the first place. Because of the marriage’s clandestine character, the Church was frequently placed in the intolerable situation of not being able to demonstrate that the marriages were real. 

To confront problems associated with clandestine marriages, the Council of Trent instituted certain mandatory guidelines for the conducting of marriages. And it established these as a condition for validity, which means that a failure to conform to the proper form renders a marriage void from the beginning.

Material or Formal Cooperation

Which brings us to the key question: Is it legitimate to attend the wedding of a couple who are marrying invalidly?

The Catholic Church does not have a specific teaching on the question of attending invalid marriages, and faithful Catholic commentators take differing positions on the question. 

In my judgment, attending such a ceremony is morally dangerous and frequently not legitimate — but if certain precautions are undertaken, it can be legitimate. Let me explain.

To morally assess this question, we need to consider what is called material cooperation in the wrongdoing of another person(s). Material cooperation refers to some act by which we unintentionally facilitate another’s bad act. 

It is not hard to see that by attending the ceremony of a couple who is marrying invalidly, we facilitate — however minorly — their bad act. But we don’t intend to facilitate it; we only accept the harm caused by our attendance to avoid other harms that would occur if we didn’t attend.

To determine whether accepting this kind of harm is legitimate, we need to answer the question: Do the harms — the bad effects — caused by attending the wedding ceremony provide stronger reasons for attending it than the harms caused by not attending it?

Alienation or Scandal

The major bad effect of not attending the ceremony is alienating the couple, and perhaps other family members and friends. You, of course, want to be as supportive as is consistent with good morals, and you don’t want to alienate relationships unnecessarily. 

The strongest (though not the only) bad effect of attending the ceremony is the risk that your presence there will cause scandal — that is, will lead another into sin. 

If you have good reason to think that attending the ceremony is likely to cause scandal, albeit unintentionally, you should not attend unless you think that not attending would have an even worse effect — and that is hard to imagine. One possible example of a worse effect of not attending the wedding would be that it causes another person — someone who is otherwise open to entering or returning to the Catholic Church — to be so alienated by your choice that all such openness vanishes. 

There are several ways that scandal might occur.

The first regards the couple themselves. They know you are a committed Catholic. If you attend the wedding, your presence may wrongfully reinforce in their minds the conclusion that what they’re doing is legitimate and that they are really getting married. 

A second regards others who know you are Catholic. They may conclude that you think what the couple is doing is legitimate, which could make it easier for them mistakenly to conclude that marrying under similar circumstances is not morally prohibited. 

Finally, if you bring your children to the ceremony, you risk giving them a very bad example about the nature of marriage, an example that could have tragically bad effects later in life when they are considering marriage.

Near Occasion of Sin

Another consideration. If you attend, you might feel pressure to offer praise or flattery that implies you believe the marriage is real (“That was a beautiful service;” “I love your dress”). Or out of a desire for human respect, you might stay silent when you otherwise should say something. 

You know that if you express your convictions, it may come across as “judgmental” or “mean” — things you appropriately wish to avoid, because they could be more alienating than not attending in the first place. All this might tempt you to compromise your values by acting as if you think the couple is doing something good. 

If you believe that attending the wedding would place you in a near occasion of sin in these ways, you should not attend.

Final Considerations

But if you can confidently avoid scandal, and if you are reasonably sure that you would not be placing yourself in a near occasion of sin, then attending the ceremony can be morally legitimate.

In my judgment, you should consider certain measures to help avoid giving the impression that you support what the couple is doing.

First, communicate, without any harshness, to the couple that you do not believe their marriage will be valid, and explain to them the reasons for your conclusion.

Second, decline any invitation to take a role in the wedding ceremony, whether that be as a bridesmaid or groomsman, reader or musician, candle lighter or guestbook attendant. (Indeed, these are all examples of formal cooperation and as such would never be legitimate.)

Third, avoid attending the reception or giving a gift, and sit in an inconspicuous place (e.g., the back) in the church or wedding hall.

Taking precautions such as these will communicate to the couple, directly or indirectly, your convictions about the morality of what they are doing. And other people will be less likely to draw morally wrongful conclusions from your presence at the ceremony, conclusions that might adversely affect their own behavior and eternal destiny.