'...He was taking too much for granted'

[zgirnius]

No: HPFGUIDX 161454

chrustoxos: 
> So that's it. Any idea on what DD was asking SS to do, taking for
> granted that he'd do it?
> 

zgirnius:
I think they were discussing the Draco problem. Dumbledore was telling 
him to keep watching his moves and discourage him from any further 
attempts like the necklace. Snape had already failed to get through to 
Draco in the conversation we saw during Slughorn's Christmas party. 
Just before the conversation, he had probably noticed Draco was up to 
something new (if Harry noticed Draco disappearing for hours, surely 
Snape would). He may have been telling Dumbledore he was not sure he 
could stay in top of the problem. This also fits in with Dumbledore 
tellin Snpae to continue the investigation 'in his house'.

Another idea I had was that they may have been discussing plans for 
after Snape leaves Hogwarts. It is my opinion that they assumed Snape 
would be forced to leave Hogwarts by the DADA position curse, and 
probably planned for him to do so as the apparent murderer of 
Dumbledore.

So I think Dumbledore was saying Snape should say close to Voldemort, 
to spy on him, or possibly be near to help Harry in the final 
confrontation.