What triggered ancient magic? WAS: Re: James and Intent

[montavilla47]

No: HPFGUIDX 187004

> > > Carol responds:
> > > I agree with Montavilla47. In fact, I thought it was canon that Snape's request to Voldemort to spare Lily's life followed by Voldemort's broken word was what distinguished her sacrifice from any other mother's--and from James's. As Dumbledore insists to Harry and Voldemort also tells him, Lily could have lived. <SNIP>But then Voldemort, who could have kept his word and merely Stunned her, decides to kill her as well. And that decision, as I understand it, triggered the ancient magic that made her sacrifice, her exchange of her own life for Harry's, into ancient magic. <SNIP>
> > 
> > Alla:
> > But if you say that Snape's bargain and Voldemort's agreement are what triggered the ancient magic, I would certainly appreciate some canon about it.

Montavilla47:

Carol did an excellent job at citing the canon.  It's never, to my knowledge,
stated outright that the difference was Voldemort giving the Lily the choice to
step aside that made the difference, but there is no other explanation.

We see other mothers protecting their children without Voldemort getting
vaporized.  The sacrifice that James made in protecting his family did not
trigger the magic, either.

The thing that distinguishes Lily's sacrifice is that she was given a choice
and she chose to protect her child.  

So, I'm not saying that it was Snape and Voldemort who triggered the 
special blood protection.  It was Snape's request, *plus* Voldemort's 
agreement to that request, *plus* Lily's refusal to step aside, *plus*
Voldemort's breaking his word to Snape that triggered the magic.