The Good Thief and Baptism

Does not the example of the Good Thief on the cross (cf. Lk 23:39-43) disprove the necessity of baptism for salvation?

[For a more general discussion concerning baptism, please see this previous post I have written here].

No, it does not disprove it, and below are three reasons that it would not. 

First, the reception of baptism appears to have become mandatory for salvation only after the passion and resurrection of Christ, for reasons explained by St. Thomas Aquinas in the Summa Theologica (specifically, IIIa, q. 66, a. 2.) That being the case, then since the Good Thief had died before then, such an obligation was not applicable to him any more than to Abraham.

Second (and even more importantly), the necessity of baptism is simply regarded as a normative necessity, *not* an absolute one. The Church has always recognized, to quote the Catechism of the Catholic Church, that "God has bound salvation to the sacrament of Baptism, but he himself is not bound by his sacraments" (CCC #1257). Rather, the Church also recognizes what is known as "baptism of blood" (for those who are martyred before receiving the sacrament), as well as "baptism of desire" (for those who would have received baptism if they had known of its necessity or have had the opportunity). God obliges no one to the impossible. So even assuming for the sake of argument that the Good Thief had lived at a time when baptism was obligatory, clearly he would have had baptism of desire while on the cross. 

Finally, while the above are the two main factors to take into account, it also occurs to me that the objection above makes an assumption that we cannot at all be certain of, namely, that the Good Thief had *not* in fact ever been baptized. But how can we know that? Of course, it is possible that he never was, but it is also quite possible that he had been baptized. Not knowing anything of his prior life, we don't have enough information to know either way. 

After all, while the baptism of Christ was not obligatory at that point as it would be later on, still it was administered during his ministry (cf. Jn 4:1-2). Consequently, it is quite possible that the Good Thief had been baptized, but simply fell away (say, perhaps, after the Bread of Life discourse in John 6, when many of Christ's disciples left him; cf. Jn 6:66). If so, then like many people who have fallen away from Christ since, he could have fallen into an evil life before returning (like the prodigal son) before it was too late. If so, it would not be the last time such a thing would happen, though it may have been the first. 

Indeed, under such a scenario, that would explain quite well why he appears to have first mocked Christ (cf. Mk 15:32), but afterwards repented and turned to him in faith. Such a sudden conversion (perhaps after seeing Christ's example on the cross) and acknowledgement of His kingship is far more comprehensible if the Good Thief had had some prior familiarity with Christ, even being a follower at some point, than if Christ was a complete stranger to him or only a subject of vague rumors. 

To be clear, I am not saying that the hypothetical scenario I presented above is in fact the case. Obviously, I do not know. Rather, I am simply meaning to emphasize that we do not have enough knowledge to know (one way or the other) if the Good Thief had ever received Christ's baptism. It is presumed far too easily that he had not, but on insufficient grounds. But if he had, then obviously the example of the Good Thief fails as an objection to the necessity of baptism (quite apart from the first two reasons I gave above.)