Thanks for the ping...
SPOILER!
I haven't scrolled through everyone's remarks as yet, but I'm surprised that no one has brought up the Unbreakable Vow Snape made with Narcissa at the beginning of the book. That's the whole reason, imo, that Snape killed Dumbledore...if he didn't keep his vow to Narcissa, he would have been killed himself. No doubt (it's likely Dumbledore knew about the Vow, if Snape really IS loyal) this is why Snape was so adamant about not being a coward when Harry accused him of being such. Dumbledore and Snape probably worked this out ahead of time, to a certain extent. Snape was likely not happy to be killing Dumbledore, when he (meaning Dumbledore) had gone out on a limb for Snape and defended Snape against everyone who doubted his loyalty to the Order and to Dumbledore. But, the Vow was made, and there was no getting around it...and Snape was supposedly spying on Voldermort and the Death Eaters. Not easy to replace him, after all.
Speculation is fun! :)
I think you could be right. When Snape was making the Unbreakable Vow, his hand twitched and he hesitated before promising to do what Draco couldn't.
I think Snape took the Unbreakable Vow with Narcissa because Dumbledore told him too. He would have to prove to the Death Eaters that he was their man, to win trust that will lead to the death of Voldemort. He will have to find Harry in the next book and convince him of this, I think.
By the way, does anyone think that Harry's parents may come back in the last book? I don't think they are dead because of him not being able to see Thestrals until watching Cedric die. Perhaps James and Snape will come together to help Harry kill the Dark Lord....who knows, maybe that is how Snape will win Harry's trust. I can't wait until the next book. Regulus Black. I knew I knew the initials from somewhere. I also thought that we were being set up for something being hidden in the Room of Requirement when she went into such detail about hiding the HBP's potions book.
True. I'm also wondering if Dumbledore's trust in Snape may have something to do with a previously-made Unbreakable Vow...
Of course, it became apparent to me very quickly that he [Harry] had no extraordinary talent at all. He has fought his way out of a number of tight corners by a simple combination of sheer luck and more talented friends. He is mediocre to the last degree, though as obnoxious and self-satisfied as was his father before him. (emphasis mine)
That's an odd thing for someone to say if he's NOT loyal to Dumbledore. We have been told by several people that Harry has the makings of a very powerful wizard, even though his grades in school may be less than desired. He is, for example, very skilled at DADA. We know he has conjured up a Patronus, which we are told on several occasions is a very difficult thing to do, and not something that dumb luck would help him with.
It's in the Order of the Phoenix's best interests for the Death Eaters to think that Harry is incompetent and the beneficiary of good friends and dumb luck, because then they might take him less seriously than they ought.
I'm taking my sweet time on this re-read of HBP, and then (hopefully before GOF comes out this fall) I'll tackle the entire series again. This is FUN!