Sirius, The Fidelius Charm, and You-Know-Who

[carrie1138]

No: HPFGUIDX 33722

Speculating on the workings of the Fidelius Charm, Marina wrote:

For the big secret it was supposed to be, it seems like an awful lot 
of people knew where the Potters were. <snip>
Flitwick says that Voldemort could be looking through the house 
window and still not see the Potters because of the charm. Perhaps 
Voldemort would go temporarily deaf if he ever questioned someone who 
knew where the Potters were, but was not the actual secret-keeper. 
So, even if Sirius was not the keeper but still knew where the 
Potters were hiding, he could scream out the Potters' whereabouts 
until he was blue in the face and Voldemort would never hear him! 
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The Fidelius Charm does seem like a very complicated piece of spell 
work. Flitwick has to explain it to Madam Rosmerta in the Three 
Broomsticks (though that may be a literary device so Harry -- and the 
audience -- get to hear the explanation), and the wording of the 
explanation is, I think, deliberately vague. "The magical concealment 
of a secret inside a single, living soul". The "secret" here seems to 
be not merely the specific knowledge of the Potters' location, but 
something else, almost (this is the way I see it anyway) a physical 
representation of the secret. I can't explain this very well, it's 
not exactly clear in my mind either, but if you think of the secret 
as something separate from the actual knowledge it's a bit easier. 
Imagine something like the silver threads that are Dumbledore's 
thoughts as he puts them into the Penseive. The "secret" is taken 
from all who know it, so Dumbledore, Sirius, Lupin, Hagrid, etc, all 
give their knowledge of the secret, put it in something like a 
Penseive maybe, and then James and Lily perform the Charm and 
transfer the "secret" to Pettigrew. In this case, everyone who knew 
where the Potters were still have that knowledge, but maybe they 
can't articulate it. Maybe even if Sirius said to Lupin, "Let's visit 
James and Lily. Where are they staying again?" Lupin wouldn't be able 
to tell him, couldn't remember or whatever, but if they set out to go 
there, they could still find the place. 

Cindysphynx wrote:
If revelation of the location of the Potters had to be voluntary, 
however, why would Voldemort bother to try to track down Sirius the 
Secretkeeper at all? Voldemort would know it would be futile to 
pursue the secretkeeper, who would just refuse to reveal the secret? 

I wonder if Sirius was worried Voldemort would place him under the 
Imperius Curse and obtain the Potters' location that way.
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Imperius definitely seems a possibility, it can make people do things 
they would not choose to or even be able to do (witness Neville's 
gymnastics!). But Voldemort seems to be a highly skilled wizard, 
judging by what we see him do in the series. He can conjure a hand 
out of thin air, create a potion to give himself a body, possess 
others and speak out of the back of their heads, even break powerful 
memory charms while in a severely weakened state. So I'm sure that as 
soon as he knew the Potters were using the Fidelius Charm, he would 
be working on some way of breaking it.

This is my first post here, so I hope it made sense!

Carrie1138 (with apologies to the other Carrie I've seen on this 
list!)