That's a new one. How did Draco almost help Dumbledore?


Voldemort's motive is that he's mad at Lucius. Draco was happy about it in the beginning.


The Plan was a joke, from the beginning. The possibility of Draco succeeding was never entertained. I can understand Voldemort telling Snape about it:
(1) Voldemort is a basically sadistic person and would enjoy a good gloat. Considering Snape's on-going pose as a psychopath, Voldemort probably expected Shape to enjoy the story.
(2) Because of Snape's position, he could turn it into a real Plan. He could let Draco "own" the plot until the last minute, thus protecting his status as Voldemort's spy if the Plan were aborted. He might even be able to keep his position and blame the murder on Draco after the fact. It's the type of thing Voldemort does.

(3) This murder would be the ultimate test of Snape's loyalty to Voldemort. Voldemort couldn't lose. If the Plan failed, Snape would be exposed as a traitor. If the Plan succeeded, he would be rid of Dumbledore AND he would be sure of his now-most-faithful servant, Snape. By the Bellatrix standard, Snape is intelligent, reliable and emotionally stable. Truly a prize. Voldemort would have a useful servant at last.


Snape knows Voldemort. He wouldn't need to ponder long to figure out Voldemort's next step. Assuming that Draco failed, Voldemort would order somebody to kill Draco. And the somebody would probably be Snape: (1) because Snape is right there, at Hogwarts; and (2) if the Plan failed, Voldemort would very reasonably assume that the failure was Snape's fault, and that Snape was a traitor. Voldemort would have fun playing with Snape over who/how/when to kill Draco, and then Snape would die, too. Even before Narcissa's visit, Snape's life was already depending on Dumbledore's apparent "death."

Voldemort certainly knew about the Vow, probably soon after it was made. If Bellatrix or Peter didn't immediately run to Voldemort with the news, Shape would have done so at his first opportunity. Snape would be crazy not to tell him. Snape made the Vow to protect himself and Draco from Voldemort. If Voldemort doesn't know about it, that would defeat the whole purpose of the Vow.

The best part is that Voldemort can't complain about the Vow. He has probably already hinted to Snape that Snape will be expected to finish the Dumbledore job. Voldemort probably didn't mention that he will then ask Snape to turn around and kill Draco, too. Snape is a smart boy, but he can play dumb.

Voldemort was probably pleased with the Vow. To Snape, it was an act of defiance, but Voldemort would see it as a sign that Snape is taking the Plan seriously.