Mistress Siana wrote:There are various reasons why think that Snape can impossibly be a spy:
1) Quirrel. He shared his body with LV, so Snape would have noticed because of the Dark Mark. Why else would he have found out in the first place? And LV certainly knows about that.
Snape noticed the Death Mark because Voldy was wanting him to. It burned the night of GoF because Voldy intended it to burn. It only burns and turns really bad when Voldy wants to call his Death Eaters. In P/SS, Voldy had no intention of calling anyone, being in the state he was in...
2) The trial in which DD vouched for Snape was a public one. If you consider Malfoy's connection to the ministry, it seems very unlikely that he doesn't know.
Could be, but we don't really know the rules about that... and it could be that Malfoy was thinking Snape was just trying to keep his nose clean, just like he was... Remember, after Voldy was supposedly conquered by 1-year-old Harry, Death Eaters started telling all kinds of stories to get out of trouble... Dumbledore's saying Snape turned spy, the way it was worded, doesn't necessarily mean that Dumbledore
knew about it at the time... I know that doesn't make as much sense as it does in my head, but, like, Snape told Dumbledore that he became spy before, but it can be assumed by someone not wanting to believe it that Snape didn't go to Dumbledore to become a spy...
3) Letting Snape teach occlumency, which contained the risk of Harry breaking into Snape's mind, as it happened in the end would have been too dangerous. I know there has been the argument that Snape teaching Harry and Snape facing LV directly wouldn't have made a difference. but DD saw a danger in teaching Harry himself, whereas the direct confrontation with LV at the end didn't seem to cause im any problems. So there must be some kind of difference.
Personally, I think Snape is better at Occlumency than Dumbledore is. Also, unfortunate as it is to say it, Dumbledore is a teeny bit more valuable than Snape is, all things considered. If I'm right, and Snape is more skilled at Occlumency than Dumbledore, then the risk would be greater for Voldy to break into Dumbledore's mind through Harry than it would be to break into Snape's mind... Not to mention, Snape takes plenty of precautions, so on top of being the best at Occlumency, he uses the Pensieve and keeps less harmful thoughts and memories at the forefront... also, it's possible, if, as I think, Voldy doesn't suspect Snape, that he wouldn't even bother breaking into his mind.