why didn't cardinal Siri eventually tell the truth about him being usurped from the papacy and blackmailed or threatened, especially right before he died? by then he would have nothing to lose nor fear to tell the truth.

A priest just told me that the Cardinals take an oath of secrecy in a Conclave - probably this is common knowledge. Then, if anything is leaked about the goings on at the Conclave, somebody is guilty of perjury. Serious sin anyway. Wouldn't life be simpler if any inside privileged info about any conclave was dismissed on grounds of perjury? Accessory to a sin by spreading the "rumors"? Jus' sayin'

So, other objections to Siri Theory ...

1) Siri lost the papal office since he accepted Vatican II.

2) Siri was a coward.

3) Was Siri unaware that he was the pope?  If not, how could that be?

Respondeo:

1) There are many people who accept V2 without pertinaciously adhering to any error in it, much less to any heretical proposition.  Simply being in material error about V2 does cause loss of membership (and therefore loss of office) in the Church.  No one has ever produced a single heretical proposition ever uttered by Siri.

2) So?  That has nothing to do with whether he was pope.  Apart from that, it's very easy for our valiant armchair keyboard warriors to declare this.  Let's say someone threatened to exterminate your entire extended family or threatened to kill all bishops and priests behind the Iron curtain or to nuke the Vatican (various opinions about the nature of said threat that are out there).  Until you're in that situation, just shut up about accusing anyone else of cowardice.  I'd like to think that I wouldn't cave, and perhaps if he felt it was a matter of faith, where they threatened these things unless he rejected Christ, perhaps at that point he would not have given in.  But just to be pope?  He may have thought it was just political and not a matter of faith, where they didn't like him for one reason or another.  He's reported to have said in response to these threats:  "If you don't want me, pick someone else."  He may not really have wanted to be pope anyway.  He didn't think perhaps that this would result in the selection of an AntiPope, but just some other guy they wanted instead of him (as per his comment).

3) You can be mistaken about an assessment of your own state, and in fact often are.  So Siri gets threatened.  He steps down.  Since in his mind, he may not really have wanted to be pope anyway and knowing that he has free will ... he judged it inside his own mind to have been an act of free will.  And it was on one level.  Even if I'm under grave pressure, I could still say no ... and whatever I do would still ultimately be an act of free will, and in one sense a free choice.  But that is not the sense or meaning of Canon Law, when it says that resignations made under duress are invalid.  EVERY RESIGNATION just as every human act is an act of FREE WILL.  Even if I had a gun to my head, I could say no and take the bullet.  Of course, in that case they would have forced me to "resign" via the bullet anyway.  Yet that is not what is intended.  Basically, if you WOULD NOT HAVE RESIGNED were it not for the duress, that's legally not considered a free resignation (even if ultimately in an absolutely sense it's still an act of free will, since you can say no).  But that line between the two can blur in your own mind, especially if you were reluctant to accept in the first place.

Whether or not Siri was elected we'll never know.
If he was and then turned it down he was a coward and
unfit to be pope, bishop or even a priest. 
As a bishop he is expected to lay down his life for his flock.
I don't buy that a bunch of effeminate
freemasons told him in front everyone in the Sistine Chapel 
that he and/or his family would be killed unless
he stepped aside. If they did there could have been any number of 
ways to deal with them. As pope he would have his own personal
security team. He could have picked up the phone and asked for
the protection from the Italian government...or any number of 
foreign governments. Or called upon the assistance of roughly
a BILLION loyal Catholics who would have volunteered to protect
him 24/7. 

Whether or not Siri was elected we'll never know.

You now this, how ... of prophet?

If the two got excommunicated, then John XXIII must have been Pope to wield such authority. Or at least the cardinals didn't know what was going on regarding Siri. What happened to those cardinals?  A quick apology and the excommunication lifted?

Sigh ... he could simulate the wielding of papal authority, just as he simulated teaching authority at Vatican II.

As for whether the other Cardinals not knowing what was going on, this has been dealt with.  Most likely what happened is that after he accepted, in the "Room of Tears", there are probably only a small handful in there.  Those go in, issue the threats, and then Siri comes out and says that he's changed his mind and is stepping down.  Nobody but a few had to know the details of what transpired in there.

Nevertheless, the fact of acceptance and then a "resignation" within minutes ... would have caused quite a stir, and it's likely what Roncalli held the after-conclave meeting about, for people not to leak it out that Siri had accepted then resigned, since it would cause consternation among the faithful, ahem, especially after people would have started digging more into what happened and possibly uncovered the truth.

So Roncalli gave strict orders for no one to speak of the "irregularity".  In fact, I think it may have been Siri or some other Cardinal involved who use the term "irregularity".

... and all that of course calls to mind the prophecy of St. Francis of Assisi about the "uncanonically elected pope" who turns out to be a destroyer.

Yeah, here comes the keyboard armchair warrior.  I already anticipated this.  Let's have someone threatent the lives of your entire extended family or all the priests and bishops behind the Iron Curtain.  Heck, if they threatened your life with one or another cruel torture, you'd probably piss your pants and without the grace of God would reject the faith.

Sit there all you want, sanctimonious, high and mighty and declare him a coward.  So what, lame-brain?  We've had selfish, self-absorbed, cowardly popes throughout the Church's history, some degenerates ... none of that makes them non-popes.

Not only my life but the lives of my immediate family weren't simply threatened with words but with actual gunfire.
In total I've been shot at on two separate occasions. I've also had someone try to stab me to death. 
And no, I didn't piss my pants. In fact, the complete absurdity of it amused me. 
My faith and the well being of Christ's one true Church wasn't even on the line...so I'll repeat, if Siri was elected and caved he had no business ever taking up the crozier. The potential for martyrdom goes with the territory.

From why I've gleaned reading your otherwise insightful posts on doctrine and church history you were a former seminarian. It's probably a good thing you couldn't cut it at priest as you clearly lack patience, humility and the ability to hold your tongue given your propensity to hurl invective at the drop of a hat. 
I was wondering when it would be my turn to be on the receiving end of it. Try to work on that my friend. 

SVism chokes and can't provide an answer.  Why?  Because no one has ever produced a single shred of evidence that Montini was a manifest heretic outside his teaching at Vatican II.

So the "manifest heresy" angle results in epic fail.

So we are clear: V2 does, in fact, suffice as evidence of such manifest heresy?  If so, is there some reason that such evidence is somehow insufficient to conclude that, at best, he lost authority (if he had it at all)? 

I presume you know about and have read Fr. Ricossa's series of articles about Roncalli.

Just now reading your reply to previous post...

So it is your position that neither could have possessed and lost the Papacy.  They absolutely must have never been Pope.

You do not believe it is possible for a man (J23/P6 aside) to truly be Pope and lose said office? 

But there were 18 cardinals who participated in the two conclaves in 1978 (because remember JP I died suddenly) who were created cardinals by Pope Pius XII.  This meant that a sitting pope (Siri), together with 18 other cardinals, voted in back-to-back conclaves knowing that Siri was the legitimate pope.  I still submit that it is a long stretch to say that 18 cardinals were so weak as to not say a peep.  These same cardinals also voted in the conclave to elect Paul VI.

I am not ruling out the theory outright, as there is the slim chance that the Siri theory is legitimate.