I speak of those who was never baptized in the church. Baptism is essential to salvation so what is the church’s view on this issue?
A person who was never baptized because he or she never heard about Jesus and never had the opportunity for baptism may be able to cooperate with God’s mercy in a way that allows that person to be saved. Such people may well have explicitly desired baptism had they known of it, so this is known as the “baptism of implicit desire.”
Anyone who had full knowledge of the effects of baptism but refused it anyway would be in considerably worse shape, although we can’t say for sure what any individual’s fate would be in that case.
Lumen Gentium talks about this in detail, specifically paragraph 16, and also paragraphs 14 and 15.
may be able to cooperate with God’s mercy ---- How does one qualify for this cooperation? Does the person have a choice in this matter?
By being loved by God and recognizing, and living by, the law that is written on their heart.
Does the person have a choice in this matter?
Always (free will)
So where does one receive the cooperation that you refer to?
It is a gift from God. (Grace)
So where does baptism happen for the dead, based on the cooperation you spoke of?
There is no baptism for the dead. There is a term that the Catholic Church teaches.
Those converts who died prior to their baptism, are baptized by blood.
Christians have always interpreted the Bible literally when it declares, “Baptism . . . now saves you, not as a removal of dirt from the body, but as an appeal to God for a clear conscience, through the resurrection of Jesus Christ” (1 Pet. 3:21; cf. Acts 2:38, 22:16, Rom. 6:3–4, Col. 2:11–12).
Thus the early Church Fathers wrote in the Nicene Creed (A.D. 381), “We believe in one baptism for the forgiveness of sins.”
And the Catechism of the Catholic Church states: “The Lord himself affirms that baptism is necessary for salvation [John 3:5]. . . . Baptism is necessary for salvation for those to whom the Gospel has been proclaimed and who have had the possibility of asking for this sacrament [Mark 16:16]” (CCC 1257).
The Christian belief that baptism is necessary for salvation is so unshakable that even the Protestant Martin Luther affirmed the necessity of baptism. He wrote: “Baptism is no human plaything but is instituted by God himself. Moreover, it is solemnly and strictly commanded that we must be baptized or we shall not be saved. We are not to regard it as an indifferent matter, then, like putting on a new red coat. It is of the greatest importance that we regard baptism as excellent, glorious, and exalted” (Large Catechism 4:6).
Yet Christians have also always realized that the necessity of water baptism is a normative rather than an absolute necessity. There are exceptions to water baptism: It is possible to be saved through “baptism of blood,” martyrdom for Christ, or through “baptism of desire”, that is, an explicit or even implicit desire for baptism.
Thus the Catechism of the Catholic Church states: “Those who die for the faith, those who are catechumens, and all those who, without knowing of the Church but acting under the inspiration of grace, seek God sincerely and strive to fulfill his will, are saved even if they have not been baptized” (CCC 1281; the salvation of unbaptized infants is also possible under this system; cf. CCC 1260–1, 1283).
As the following passages from the works of the Church Fathers illustrate, Christians have always believed in the normative necessity of water baptism, while also acknowledging the legitimacy of baptism by desire or blood.
“‘I have heard, sir,’ said I [to the Shepherd], ‘from some teacher, that there is no other repentance except that which took place when we went down into the water and obtained the remission of our former sins.’ He said to me, ‘You have heard rightly, for so it is’” (The Shepherd 4:3:1–2 [A.D. 80]).
“As many as are persuaded and believe that what we [Christians] teach and say is true, and undertake to be able to live accordingly . . . are brought by us where there is water, and are regenerated in the same manner in which we were ourselves regenerated. For, in the name of God, the Father and Lord of the universe, and of our Savior Jesus Christ, and of the Holy Spirit, they then receive the washing with water. For Christ also said, ‘Except you be born again, you shall not enter into the kingdom of heaven’ [John 3:3]” (First Apology 61 [A.D. 151]).
“Happy is our sacrament of water, in that, by washing away the sins of our early blindness, we are set free and admitted into eternal life. . . . [But] a viper of the [Gnostic] Cainite heresy, lately conversant in this quarter, has carried away a great number with her most venomous doctrine, making it her first aim to destroy baptism—which is quite in accordance with nature, for vipers and asps . . . themselves generally do live in arid and waterless places. But we, little fishes after the example of our [Great] Fish, Jesus Christ, are born in water, nor have we safety in any other way than by permanently abiding in water. So that most monstrous creature, who had no right to teach even sound doctrine, knew full well how to kill the little fishes—by taking them away from the water!” (Baptism 1 [A.D. 203]).
“Without baptism, salvation is attainable by none” (ibid., 12).
“We have, indeed, a second [baptismal] font which is one with the former [water baptism]: namely, that of blood, of which the Lord says: ‘I am to be baptized with a baptism’ [Luke 12:50], when he had already been baptized. He had come through water and blood, as John wrote [1 John 5:6], so that he might be baptized with water and glorified with blood. . . . This is the baptism which replaces that of the fountain, when it has not been received, and restores it when it has been lost” (ibid., 16).
“[P]erhaps someone will ask, ‘What does it conduce unto piety to be baptized?’ In the first place, that you may do what has seemed good to God; in the next place, being born again by water unto God so that you change your first birth, which was from concupiscence, and are able to attain salvation, which would otherwise be impossible. For thus the [prophet] has sworn to us: ‘Amen, I say to you, unless you are born again with living water, into the name of the Father, Son, and Holy Spirit, you shall not enter into the kingdom of heaven.’ Therefore, fly to the water, for this alone can extinguish the fire. He who will not come to the water still carries around with him the spirit of insanity for the sake of which he will not come to the living water for his own salvation” (Homilies 11:26 [A.D. 217]).