Sicut sacram ergo paschalem reverentiam in nullo dicimus esse minuendam, ita infantibus qui necdum loqui poterunt per aetatem vel his, quibus in qualibet necessitate opus fuerit sacra unda baptismatis, omni volumus celeritate succurri, ne ad nostrarum perniciem tendat animarum, si negato desiderantibus fonte salutari exiens unusquisque de saeculo et regnum perdat et vitam.

So while we say that the reverence for Easter [my comment:  when Baptisms were normally done] should not be diminished in any way, so it is our will that, in the case of infants who can not yet speak on account of their age, or in the case of those would have any kind of urgent need for the waters of Baptism, that they be given succor with all haste, lest it endanger our souls, were each and every one leaving this world to forfeit both the kingdom and life by denying the Saving Font to those desiring it.

It's clearly nothing more than a piece of theological speculation that the Church has permitted.  And, in and of itself, if applied to, say, a catechumen who has all the other proper dispositions to receive the Sacrament, it does no harm to Catholic ecclesiology or soteriology.  Where it becomes a real problem is where it gets extended even to infidels.  There's no evidence that any top tier Catholic source (pope, Doctor, or saint) ever believed that BoD could apply except to the case of a catechumen.  Holy Office rejected the notion that lack of belief in at least the Holy Trinity and Incarnation were necessary for supernatural faith and therefore for salvation.  St. Robert ONLY applied it to catechumens, asking "Whether catechumens who [died before receiving the Sacrament] could be saved."  Pope Innocent was talking about a "priest" who had not been baptized (again, not sure how that's possible).

Backing for BoD is incredibly weak, and 99% of its proponents don't care about the isolated case of a catechumen who may have died before Baptism.  What they care about is using it as a weapon to undermine EENS and to use it as the mechanism by which non-Catholics (even infidels) can be saved.

So, people claim that Catholics MUST believe in BoD.  OK.  Well, what must I believe about it? 

The statement that the Church (not merely the “soul” or the “body” of the Church) is necessary for salvation with the necessity of means in such a way that no man can be saved unless he is within the Church either in re or by either an explicit or an implicit votum must be considered as an accurate statement of the revealed teaching on the Church’s necessity for eternal salvation and as the standard terminology of most modern theologians on this subject.



http://www.catholicapologetics.info/modernproblems/ecuмenism/members.htm

What I don't fully understand is how after all this time, faithful Catholic people are able to convince themselves that Trent left a loop hole, or was not clear, or could contradict Scripture, or heaven help us, taught a BOD.

On Justification, Trent clearly states that justification cannot be effected without the sacrament. What else needs to be said? And if in the future a council defines it again, what words would they use to clarify that which is already clear?


 

Session 6, (Decree on Justification)
Chapter 4

"By which words, a description of the Justification of the impious is indicated,-as being
a translation, from that state wherein man is born a child of the first Adam, to the state
of grace, and of the adoption of the sons of God, through the second Adam, Jesus
Christ, our Saviour. And this translation [to justification], since the promulgation of the Gospel, cannot
be effected, without the laver of regeneration, or the desire thereof, as it is written;
unless a man be born again of water and the Holy Ghost, he cannot enter into the
Kingdom of God."

Then in the 7th session, (On the Sacraments in general) Trent anathematizes whoever says the sacraments are not necessary for salvation....

Canon 4
If any one saith, that the sacraments of the New Law are not necessary

unto salvation, but superfluous; and that, without them, or without the desire thereof,
men obtain of God, through faith alone, the grace of justification;-though all (the
sacraments) are not indeed necessary for every individual; let him be anathema.

Also 7th session, (On the Sacrament of Baptism)

CANON II.-If any one saith, that true and natural water is not of necessity for
baptism, and, on that account, wrests, to some sort of metaphor, those words of our
Lord Jesus Christ; Unless a man be born again of water and the Holy Ghost; let him
be anathema.

CANON V.-If any one saith, that baptism is optional, that is, not necessary unto
salvation; let him be anathema.