The UV

[pippin_999]

No: HPFGUIDX 156021

Lupinlore:
> For instance, did Snape realize that Dumbledore, and not Harry, was 
> the target of Draco's mission?  Did he know that said mission 
> involved murder?  If Snape had been completely honest with DD about 
> the vow, why did Dumbledore tell him to "start searching with your 
> own house," after the necklace episode -- both of them would have 
> known exactly where to search. 

Pippin:
A slight correction: Dumbledore is reported to have said "summat abou'
Snape makin' investigations in his House, in Slytherin." We are told
that is not strange since all the Heads of Houses were told to investigate
after the necklace business. Hagrid thinks Dumbledore doesn't know
who is behind the necklace and poison, but Dumbledore later claims
that it was obvious to him all along that it was Draco. If this is true,
then  the investigations were a ruse "because I [Dumbledore] knew 
that you would be murdered if Lord Voldemort realized that I suspected 
you." 


On first reading, we think that LVM!Snape is trying to avoid an 
investigation of Slytherin. On later readings, it's possible that DDM!Snape
wanted Dumbledore to roll up the operation  to make sure another of 
Draco's witless attempts at murder didn't  succeed. But Draco
revealed at the Christmas party that his plan included backup.  
Dumbledore then had a further reason not to roll up the
operation: Hogwarts was safer with one known incompetent would-be 
murderer inside it than it would be if hardened DE's could enter at will.

In other words, it  wouldn't be much use to catch the kitten and 
leave the door open for the cat. If there really was a way for DE's to 
enter the castle, it would be imperative to discover what it was and 
Draco would be key. OTOH, maybe there wasn't a way for DE's to
get in and Voldemort was just amusing himself by giving Draco
a hopeless task. That's what Dumbledore seems to have thought,
but he knew he might be mistaken so he arranged for the
Order to guard the castle while he wasn't there.

Possibly Voldemort told Snape there was a plan with Draco at Hogwarts 
but didn't tell Snape what it was. Snape then offered his  help to Narcissa,
as he later did with Draco, in order to find out.  Harry himself realizes 
that this is what DDM!Snape would be expected to do, so if that's
a stupid idea, then Harry is stupid.

Pippin