Originally posted by: SK
i got to ask did you read the 6th book chaos? for one thing he didnt need to leave a note telling snape was really on their side because everyone in the order believed he was. dumbledore did not know snape would end up killing him, he didnt know to leave the order a note saying, "hey snape is going to have to kill me, but he is still on our side." also dumbledore didnt have snape make the unbreakable vow, draco's mother did.
i doubt that sirius would call anyone in his family a "blood traiter" that is the term for Purebloods that marry Mudbloods or Half-Bloods, or a non magical person, sirius wasnt a purist.
edit: harry already has a ton of potential, and he also has the information dumbledore passed on him. this is a great weapon since voldemort has no idea harry knows about the horcruxes. i think snape or slughorn will have to train harry in the next book.