‘The doctrine of the Church also recognizes implicit baptism of desire. This consists in doing the will of God. God knows all men and He knows that amongst Protestants, Muslims, Buddhists and in the whole of humanity there are men of good will. They receive the grace of baptism without knowing it, but in an effective way. In this way they become part of the Church.
The error consists in thinking that they are saved by their religion. They are saved in their religion but not by it. There is no Buddhist church in heaven, no Protestant church. This is perhaps hard to accept, but it is the truth. I did not found the Church, but rather Our Lord the Son of God. As priests we must state the truth.’
What I particularly loathe and detest about Dom Lefebvre’s writing is his extreme cynicism. He begins the first paragraph with the most outrageous lie and ends the second paragraph by saying that ‘priests must state the truth’. The doctrine of the Church has NEVER, EVER recognized baptism of Desire, neither implicit or explicit. The problem of Baptism of Desire only arose in the 13th century with the adoption of the philosophy of St. Thomas Aquinas which was based on Aristotle. Up until then the understanding of the Church had been that Will preceded Intellect, and that God would somehow get the Faith to men who sincerely desired it. The adoption of the philosophy of St. Thomas Aquinas, where Intellect has precedence over the Will, gave rise to the arcane philosophical problems of catechumens who died before receiving baptism and invincible ignorance. For an excellent and complete history of the problem of Baptism of Desire, I recommend ‘Desire and Deception’ by Charles Coulombe. Link
The crack in the edifice of the Church’s teachings about salvation was the result of vain, futile, philosophical discussions which God’s enemies pounced on and enlarged to demolish the Church when ‘ the ‘desire of a catechumen to receive baptism’ became the desire of mankind ‘to do God’s Will’.
1 Timothy ‘Who will have all men to be saved, and to come to the knowledge of the truth.  For there is one God, and one mediator of God and men, the man Christ Jesus:
One mediator: Christ is the one and only mediator of redemption, who gave himself, as the apostle writes in the following verse.
Who gave himself a redemption for all, a testimony in due times.
Thus God’s will is for all mankind to be saved and to know the Truth. But salvation can only be achieved by faith in the redemptive sacrifice of Our Lord Jesus Christ Incarnate and belief in the Truth. The Truth being those teachings expounded by Our Lord to the Apostles, and by revelation to St. Paul, and transmitted by the Church to the faithful for almost 2,000 years until Vatican II, the Dogmas of the Faith.
Dom Lefebvre skips over the details of how Buddhists who deny the existence of God, Muslims who deny the Trinity, or Protestants who deny the authority of Tradition are able to discern God’s will, and why this ability is confined to some but not all of their coreligionists. The implication is that these people somehow receive the grace of baptism and become members of the Church without desiring it, or being aware of the fact that they are so blessed! These people according to Dom Lefebvere, are walking around amongst us as ‘hidden Catholics’. How baptism can be ‘effective’ if neither the receiver of the Grace, nor anyone else for that matter perceives any difference in their behaviour or beliefs is beyond my understanding. If this were true, I can imagine the reaction of an Ulster Protestant who on arriving in heaven discovers that all his life, without knowing it, he was a member of, and owes his salvation to the Catholic Church, ‘the whore of Babylon’. I think that he would be so disgusted that he would demand to be sent to Hell straightaway!
Effectively, what Dom Lefebvre states is that that only God knows who will be saved and it doesn’t matter what they believe in or how they behave, some people are destined to be saved ‘though the Church’. This is a version of the Calvinist heresy of the “elect” who are predestined to be saved no matter what they do on earth. But the Calvinists do at least believe in Jesus Christ, God Incarnate.
Predestination is a heresy that has been strongly condemned by the Church because it denies that man has a free will.
But no less grave are the errors into which a second group falls by making God alone responsible for everything, and abolishing the free co-operation of the will in obtaining eternal happiness. This is done by the advocates of heretical Predestinarianism, embodied in its purest form in Calvinism and Jansenism. Those who seek the reason of predestination solely in the absolute Will of God are logically forced to admit an irresistibly efficacious grace (gratia irresistibilis), to deny the freedom of the will when influenced by grace and wholly to reject supernatural merits (as a secondary reason for eternal happiness). And since in this system eternal damnation, too, finds its only explanation in the Divine will, it further follows that concupiscence acts on the sinful will with an irresistible force, that there the will is not really free to sin, and that demerits cannot be the cause of eternal damnation.