Clues Convergent Redux -- Snape is a nice wizard because .....

[zgirnius]

No: HPFGUIDX 134933

 
> Alla:
> 
> I actually can say the opposite. I think that if Snape was at that 
> moment at the side of good, he would NOT have taken UV in the first 
> place.

zgirnius:
Suppose Snape does not know the task. And, suppose he truly wants to 
be a useful spy for the Order. Both Narcissa and Bella describe the 
task in terms which would have any spy *very eager* to hear more.

"It is...very secret."
"Draco should be proud," ... "The Dark Lord is granting him a great 
honor."

This sounds like it could be the secret that makes the whole double-
agent game pay off, no? But despite a lengthy conversation *around* 
the main point, neither lady drops any concrete hints. However, Cissy 
does go all emotional and desperate over her poor little Draco. Snape 
sees his opening, and suggests he could help. Narcissa then makes two 
comments, the point of which is that she hopes Snape will protecxt 
and look after Draco. Then she suggests the UV.

What does Snape expect she will ask? Why, that he protect and look 
after Draco. It's risky, but not *too* much so. Draco will, after 
all, be at Hogwarts, in his classes and House. And DD (for one) would 
be perfectly happy to help protect Draco, probably in ways Cissy 
never intended. So when Bella jumps on the suggestion, he agrees. 
It's clearly going to get the ladies to trust him more. He's oh so 
calm and collected as he agrees to clauses one and two. Then Cissy 
pops clause three on him (perform the task "if it seems Draco will 
fail"), and his hand twitches. He did not see that request coming, I 
bet, Cissy's distraught mother act worked.

I think that the mechanics of the vow are probably such that Snape 
*could* say uh-uh, Cissy, that's asking too much...but he's got his 
cover as a loyal DE to consider. And a fraction of a second in which 
to make his decision. 

This is why for me a Sincere!Snape theory is most convincing, but I'm 
very open to other explanations for the UV. (Note I do not say Good!
Snape...all this chapter suggests to me is that Snape is really 
trying to spy for DD. I do not rule out that after making this big 
mistake, Snape keeps it from DD, and kills DD to avoid the 
consequences of his own mistake. Not exactly *good*.)