Thanks to Fr. Terry Donahue and Mark Boncore for some of the technical aspects of this article.
This article is opposite to my article "How do I become Catholic?"
Recently, there were bus ads in England that said “there’s probably no god, so stop worrying about it and enjoy life.” It is part of an atheistic movement to encourage people to formally renounce their baptisms (by writing a letter and submitting it to their church).
The press has been pounding the Church for about 10 years now on a whole bunch of issues. So if you haven't been a fervent Catholic, I'm not surprised if you are thinking of leaving. If you do leave, I would say you are a casualty of this war on the Church.
I hope you don't leave. In fact, I think that would put your soul in grave eternal danger. However, God gave us free will and we can leave if we like. If you are thinking about leaving the Church you probably have not been in communion with the Church for a while. I hope you go the opposite direction instead of renouncing the Church. Some of the best Catholics are "reverts" who suddenly returned with fervor to the faith. I personally like the words of Peter:
Jesus asked him, "Will you leave me too?" He said "Lord, where would I go, you are the Word of Life?" (Jn 6:68)
"When does not being in communion with the Church turn into not being Catholic?"
When you leave the Church by a formal act.
In Canon Law, this is known as "defection from the Catholic Church by a formal act" (in Latin: actus formalis defectionis ab Ecclesia catholica). The details of how you do this practically were recently clarified by the Pontifical Council for Legislative Texts (on 13 March 2006). Here is the essential excerpt:
"1. For the abandonment of the Catholic Church to be validly configured as a true actus formalis defectionis ab Ecclesia so that the exceptions foreseen in the previously mentioned canons would apply, it is necessary that there concretely be:
a) the internal decision to leave the Catholic Church;
b) the realization and external manifestation of that decision; and
c) the reception of that decision by the competent ecclesiastical authority."
For all the details see the document here.
Baptism is an indelible permanant seal, like being born
The Actus Formulus document by the Vatican says:
It remains clear, in any event, that the sacramental bond of belonging to the Body of Christ that is the Church, conferred by the baptismal character, is an ontological and permanent bond which is not lost by reason of any act or fact of defection.
Someone can be in "apostacy", drifted away, or may have formally ceased being Catholic by writing a letter. However, once Baptism is conferred upon someone, the sacramental bond can never be undone, even though the saving grace and power can be lost through sin, or through a formal act of defection.
When I was in the gay community, I met a guy who grew up with a bad father. He changed his name because he wanted to cut all ties.
I kind of did the same thing for 10 years, even though my problems in life were mostly my own making. I didn't talk to my parents, and I wouldn't let them know where I lived and I cut all financial ties etc. (Happily, I spent the last 12 years of my dad's life very close and God healed our brokenness.)
We can renounce our parents, formally change our name and vow never see them again. We can burn pictures of our childhood. But if a scientist looks at our DNA, we will still be still our parent's child. After human birth nothing can change that basic truth. After spiritual birth, which is baptism (being born again), nothing can completely remove the spiritual DNA that joins us to our spiritual parent, the universal Church. It is an indelible spiritual seal. This is true whether the baptism was Catholic, Evangelical, Baptist or any other denomination, if it was a valid baptism, which most are. It's all the same baptism. Christ only left us one Baptism, and it is for all Christians. We are one family.
Defacto separation vs. formal separation
This is an addition from Mark Bonocore:
Every time we commit a mortal sin and are unable to licitly receive the Eucharist because we have (in a certain sense) separated ourselves from the Body of Christ. This is essentially what the Sacrament of Confession is for -- to return in repentance to full communion with the Body (the Church), from which we have separated ourselves by committing mortal sin. And, in the very early days of the Church, committing mortal sin resulted in automatic, formal excommunication from the Church. But, after A.D. 217, with the Papal relaxation of this original Apostolic discipline and the introduction of the principal of indulgences (which is the sinless Body of Christ tolerating ("indulging" members who are not-saints, still struggling to overcome repeated sins), there developed a distinction between true or essential membership in the Church (i.e., living in a state of grace and/or persistent loyalty to Catholic doctrines) and formal or institutional membership in the Church. Even if one is in a state of sin one remains an institutional member of the Church until one is either formally excommunicated or one publicly renounces their Catholic faith to embrace another faith (including atheism). In this, the Church of course continues to recognize the "mark" of one's Baptism, and so always considers this person a member of the Church, albeit a fallen away one. This is why, if one ever wishes to return to the Church (even if they publicly renounced their institutional membership), they need only receive the Sacrament of Confession to be restored to full communion.
If someone lives an unrepentant sinful life and stops going to Mass, etc., this person is technically a de facto apostate, and is no longer really a member of the Catholic Church. But, if one publicly renounces his Catholic faith, then they are more than a mere de facto apostate --they are a formal, de iure apostate, and fall under the ban of formal excommunication. Truth be told, according to canon law, this even comes into play if a non-Mass-goer fails to make what's called his "Easter duty" ...that is, receiving Confession and Holy Communion at least once a year at Easter time. Those who neglect to do this are technically apostates and de facto excommunicated from the Church. They can "fix" this problem by simply going to Confession, however. The door swings both ways. It's never too late.
Lord Jesus, let Your prayer of unity for Christians
become a reality, in Your way.
We have absolute confidence
that you can bring your people together,
we give you absolute permission to move.