A revision of a post I put on Reuters re Dutch Catholics trying to de-baptise themselves.

De-baptism? A more sensible thing to do would be to try and see if you can declare your baptism null and void even according to Church Law.

Lots of priests are modernists - ie secret liberals who believe Jesus did not found the Church or start Catholic baptism. Thus they cannot intend to baptise as the Church does - and the Church is clear and certain that baptism without that intention is not real baptism and is a waste of time.
 
The CDF in the Vatican declared that Mormon baptism is invalid for Mormons hold that baptism was not established by Jesus Christ and claims it gives the baptism of John the Baptist. The Church argues that to baptise validly you must intend to do what the Church does - ie intend to give the baptism Jesus instituted. But Mormons hold that the baptism was established in Adam's time and they intend to give the baptism of John though they use the Christian wording for the rite. Fr Luis Ladaria states, "According to the New Testament, there is an essential difference between the Baptism of John and Christian Baptism. The Baptism of the Church of Jesus Christ of Latter-day Saints, which originated not in Christ but already at the beginning of creation (James E. Talmage, Articles of Faith [AF], Salt Lake City: Desert Book, 1990, cf. pp. 110-111), is not Christian Baptism; indeed, it denies its newness." If the Mormons do invalid baptism, the modernist priest does baptism that is ten times more invalid!
 
The Bible is supposed to teach that anybody who got John's baptism needed to be rebaptised for it was not the baptism of Jesus even though John's baptism was about Jesus.
 
Acts 19:1-7 While Apollos was at Corinth, Paul took the road through the interior and arrived at Ephesus. There he found some disciples and asked them, "Did you receive the Holy Spirit when you believed?" They answered, "No, we have not even heard that there is a Holy Spirit." So Paul asked, "Then what baptism did you receive?" "John's baptism," they replied. Paul said, "John's baptism was a baptism of repentance. He told the people to believe in the one coming after him, that is, in Jesus." On hearing this, they were baptized into the name of the Lord Jesus. When Paul placed his hands on them, the Holy Spirit came on them, and they spoke in tongues and prophesied. There were about twelve men in all.
 
Modernist priests often believe that John established baptism for Jesus never intended to create a Church though Jesus got his disciples to give the baptism of John. Such then cannot give true baptism for they are even further away from Catholic belief than the Mormons.

Lots of priests are atheists or believers in something different from the Catholic God. Modernists use religious language in a symbolic way. The CDF said that Mormon baptism despite being done in the name of the Father, Son and Holy Spirit was done with the intention of denying the three in one God and so was invalid. It follows that a modernist priest whose theology of God may be even more unChristian than the Mormons cannot validly baptise. It is only a ceremony with no effect. It does not make the child a member of the Church like valid baptism allegedly does.

If you have reason to believe the priest who baptised you was a modernist at the time, then the baptism was invalid for he broke the Church rule "a valid baptism must always be performed with the intention to do what the Church does."

Finally if baptism really puts God's power and grace in you, you will know that. If you can't perceive it then clearly you have proof but only to yourself that your baptism did nothing supernatural and was not real and thus you never were a real Catholic.