Why was Lily given a chance to survive?

[zgirnius]

No: HPFGUIDX 161661

Shelley:
> Frankly, this view is the simplest and most reasonable. 

zgirnius:

I agree, though I think that there may be reasons yet to be revealed 
that would point to the fact that Voldemort chose the right boy-that 
there were factors already in play which led to Voldemort's fateful 
decision to give Lily a choice. Rowling has indicated that Alice 
Longbottom might not have been given the opportunity.

Shelley:
> We know Neville's parents were harmed too, so we 
> know that he indeed was intending very real harm to both families, 
and in 
> fact, if he had tortured the Longbottoms to get at Neville, then we 
know 
> that he failed twice. Not killing Harry would have been his second 
defeat, 
> for his first one would have been not getting information from the 
> Longbottoms on where Neville was hidden. 

zgirnius:
The Longbottoms were not tortured by Voldemort, and the information 
the torturers were after was not Neville's location. This incident 
occured after Voldemort became Vapormort. Bellatrix Lestrange and 
other diehards, for some reason, believed the Longbottoms might know 
how to find *Voldemort*. They were after this information in order to 
bring him back.