Great.  That's your interpretation for which you have no proof.  That has no impact to whether or not he was the legitimate pope.

And it's easy for you to sit in you easy chair with a beer and declare someone a coward, when you have absolutely no idea whether given the types of threats he was facing you'd buckle as well.  He had a large extended family.  What if someone told you step down as pope and shut up, or else we'll start murdering, kidnapping, and torturing your nieces and newphews.  Or we're going to round up and execute every single priest behind the Iron curtain unless you comply.  Or we're going to nuke the Vatican and a bunch of majority-Catholic cities.  Sure, he should have trusted God and gone ahead with it, but for you to sit here and judge him a coward from your easy chair, just shut the hell up.  God alone is his judge, not you.

Sorry, I didn't mean to get you riled up like that.

"The apostasy of the city of Rome from the vicar of Christ and its destruction by Antichrist may be thoughts so new to many Catholics, that I think it well to recite the text of theologians of greatest repute. First Malvenda, who writes expressly on the subject, states as the opinion of Ribera, Gaspar Melus, Biegas, Suarrez, Bellarmine and Bosius that Rome shall apostatise from the faith, drive away the Vicar of Christ and return to its ancient paganism. ...Then the Church shall be scattered, driven into the wilderness, and shall be for a time, as it was in the beginning, invisible hidden in catacombs, in dens, in mountains, in lurking places; for a time it shall be swept, as it were from the face of the earth. Such is the universal testimony of the Fathers of the early Church."

-Henry Edward Cardinal Manning, The Present Crisis of the Holy See, 1861

Maybe. He still fell into heresy by supporting and enforcing the Vatican II sect, therefore, losing any papal authority he may have had.

After much deliberation, I rescind my statement here. I still have much skepticism of the actions of Siri after the 1958 conclave, but it's clear that he was indeed elected.

I have read about the "Siri thesis", and I think it's a foregone conclusion that he was elected in the conclave, but what was supposed to be so terrible (in the eyes of his enemies) about Siri being Pope, that would prompt such dire threats and blackmail?  What was he going to do that Pius XII had not already done?  To whom did he pose such a threat?  If nuclear war were on the table, the Soviets were the only ones who would have had this capability, and would have had a reason to be threatened.  Or, for some reason, did the US not want him to be elected (Fɾҽҽmαsσɳɾყ?), and they would have been the ones to use the nukes?  Against Italy, an ostensible ally?

Or was it more a case of "because he's not Roncalli"?  Because the enemies of the Church wanted Roncalli, and that Siri's election thwarted their plans? 

I find the Siri case very compelling but the Benedict argument weak ... and I'll come back to that later.

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An oath whose purpose is to destroy the Church would obviously not be binding. In fact, it would be a sin to observe it. This is not only common sense, it is something explicitly taught to children in 1st Communion catechism class. To say that a cardinal did not know this is absurd.

This is probably the most difficult angle of the Siri thesis. I don't know of any version of it in which Siri doesn't come out as the worst coward since Pontius Pilate. At least Pontius Pilate could claim he was a simple pagan and didn't know that Christ was God, and was threatened with his life. But Siri was threatened as a cardinal of the Catholic Church and caved in, -- as pope, no less, the vicar of Christ, with the most powerful graces of state of any human being on this planet -- and consented to hand over the reins of the Church to its worst enemies, who were psychopathic mass murderers (if you believe the hydrogen-bomb-over-Rome theory), and allowed them to take over the Church?! A cardinal, who not only had (presumably) the virtue of Faith, and should have believed that God would triumph over His enemies, but also had almost 2,000 years of history behind him to see that the Church had overcome countless such attacks and persecutions and would easily triumph over this one again? How could he think it would be a good idea to allow people threatening mass murder and/or schism to take the papacy from him?

On a certain level, I don't think it matters much whether he or Roncalli won that election. I think either one was just as bad.

And if I had to choose to be in the eternal shoes of either Pontius Pilate or Cardinal Siri, I'd choose Pontius Pilate, since he was less responsible for his actions.