Why DD trusts Snape, Pettigrew and GH

[saraquel_omphale]

No: HPFGUIDX 140398

Saraquel:

I recently posted about the Fidelius Charm, and although I think I 
might have got a fairly good explanation for how it works, I had 
missed the subtlety of the situation.  I had forgotten that DD 
didn't know that Sirius was not the secret keeper.  Which set me 
thinking about the problem afresh and my thoughts came round to 
Pettigrew.

I want to float some ideas here and see if they stand up to list 
scrutiny – you lot can always be trusted to find the holes :-)

Dumbledore thinks that Sirius is the Potters secret keeper and in 
order for the least number of people to know where they are, relies 
on Sirius to keep him informed if necessary.  Are we are all agreed 
on that?

Sirius decides on the double bluff situation, as outlined by Valky 
in her post, and Pettigrew becomes the actual secret keeper.

Valky wrote:
Recall that this was a severely cloak and Dagger affair, Sirius' plan
was always intended to *hide* the indentity of the real secret 
keeper,
and bait Voldmeort to chase him to the ends of the earth where he
would gladly die with nothing to give.

At some point, *before* this happens (I'm not really up with time 
lines, so help me out if this isn't going to work) Snape comes to DD 
because he suspects that the Potters are going to be targeted by 
Voldemort, setting aside the Snape/Lily ship, the life debt could 
well be enough for his remorse.  But, what does Snape know that is 
almost guaranteed to persuade DD that he has changed sides – he 
knows that Pettigrew is a spy for Voldemort.  I speculate that this 
is the reason why DD really trusts Snape, because he shopped 
Pettigrew.

Rather than turf Pettigrew out, DD and Snape now have a cover for 
Snape, they can feed deliberate misinformation through Pettigrew and 
real but harmless information through Snape, if necessary. I'm not 
quite sure at what point Snape started to openly work at Hogwarts or 
as a 'spy' for Voldemort. If Voldemort starts to suspect a double 
agent, he will go for Pettigrew rather than Snape, or Snape can 
finger Pettigrew to Voldemort to get himself off the hook, pointing 
out that the information he has been feeding him is bogus.

At some point later on, Pettigrew is made secret keeper by Sirius. 
As far as DD and Snape were aware, Sirius was the Potter's secret 
keeper, and according to how the Fidelius Charm works, even if 
Pettigrew had known the secret he would not have been able to blab 
it to Voldemort.  Therefore neither DD nor Snape would not have 
suspected Pettigrew until Sirius turned up in PoA.  

And finally, now for the bangy bit -Why does DD not want to tell 
Harry this information – because DD and Snape kept Pettigrew in the 
Order, even though they knew he was a spy for Voldemort and they did 
not let Sirius into the loop. One of DD's huger mistakes I think.

How does that sound?

Saraquel