For those that argue from the standpoint of: I would rather
trust this or that clergyman/clergymen because they were not idiots, they were educated, prudent, etc. etc. etc. ...
Please, do not be intellectually lazy, or subjective. I am not accusing, do not misunderstand me. I am simply reminding, that
you have to answer to God for
your actions.
As I said above, this is not about making a definitive judgement, we all ought to have the humility to admit that the things Archbishop Thuc did, objectively, bring about many
real and
relevant uncertainties, to the point that the Church desires us to
treat the entire thing as doubtful. Prudent doubt, according to the mind of the Church, is important, and must be taken into account when approaching the sacraments. Probability is not sufficient certitude when it comes to the validity of the sacraments.
Do you want to do what the Church desires, or what you desire? Are we all covert modernists, where we do what we feel, thinking the truth comes from within, instead of searching for the truth without, as Our Lord ordained it to be? Humility means to conform our minds to reality, and not to create our own reality. Do not be ashamed for admitting you are wrong, or at least unsure. I will not humiliate nor hate you for it, and neither will anyone else, I am sure of it. Even if anyone would do that, we should not be afraid of enduring a little something for the love of our dear Jesus.
Please consider this: would you honestly be this defensive of a Novus Ordo Bishop, as you are of Archbishop Thuc? Or do you defend Archbishop Thuc, because you have something to lose in admitting doubt with his consecrations? Loss of friends, Mass centres, a spiritual director, the obligation to make a general confession due to confessing with a doubtfully-ordained priest, no more "peace" at home with family members, the obligation to do reparation, the simple admission of being wrong for many years? Is the cross of Our Lord truly the portion that you desire? If it is not, you will never see the truth clearly, or love it for the right reasons.

Those who defend +Thuc obstinately, as a rule, do not seem at peace, and appear to be more like those disquieted souls who thirst impetuously for their conscience to be appeased. I do not pretend, nor claim that this is automatically evidence that they are wrong, but it is something to note, for they themselves to consider.
We can only see the truth when we are at peace, and this peace is only attained when we are willing to suffer for Our Lord, whether it be in the form of keeping His commandments, or rightly perceiving the inconvenient, uncomfortable truth.
Bishop Williamson, in a conference in Post Falls, Idaho in 2013 brings to mind essential, timeless principles we must use in assessing the truth of a situation. He was teaching the faithful how they must approach choosing whether to stay with the SSPX, or join the Resistance. This is the conference, and he says these things within the first 15 minutes. https://www.youtube.com/watch?v=1uRCseOnWOw
I transcribed some of what he said, because the principles apply to any circuмstances where we are forced to make a choice, between two opposing parties.
The blame for division lies with those who are in error, and not with those who are in truth. And when the crowd listened to our Lord, they had to make up their own minds. Here were the Pharisees saying that our Lord was a liar, that he was a servant of the devil, and I know not what; and here was our Lord saying that the Pharisees were children of satan, they weren't children of Abraham, they were children of satan. Satan is the father of lies; a direct clash. How could the people know, how could the people tell? The people had to judge for themselves. And many in the crowd went one way, many in the crowd went the other; exactly the same with Vatican II. A large number of the people went with the mainstream church, because they didn't stop and think, and listen, like you yourselves most probably did 10 years ago, 12 years ago, 20 years ago, 30 years ago, when the Archbishop was standing up to the lies and the errors of the Conciliar Church. You listened, and you thought, you thunk...and because you thunk, you were not sunk; because you thought, and you listened, you examined, you tested, and that is what our Lord requires. All of you should know this quote. "I came to bring the sword"... there is going to be father against daughter, mother against son, wife against husband, uncles against aunts, there's going to be all kinds of division, because of Me. But I have to say what My Father tells Me to say, and you have to listen to what God the Father is telling you through Me, and you have to follow what I say. You must trust Me, says our Divine Lord. I don't say, trust me, trust me, trust me. I do say: look at the evidence. Weigh it for yourselves. We have here got a problem.