Why Snape turned

[justcarol67]

No: HPFGUIDX 159793

Nikkalmati wrote:
>  
> I tend for a number of reasons to think SS is DDMan and I am
perfectly willing to see him spying for over a year before he took the
job at  Hogwarts.  I would think DD would not have much faith in a spy
who worked  for him for only a few months.  But remember ST said SS
was applying for a  job at the time he was at the Hog's Head in say
10/79.. Presumably  then LV put him up to making the application.  If
DD and AD unwisely let  him go off to LV at that time, SS had to come
back to apply for the DADA  job again (but of course got Potions).  It
seems there is a bit of a  gap here.  If he switched sides once Harry 
> was born, 7/80, why didn't  he start teaching 9/80 instead of 9/81
or some earlier time.  We have seen MM and ST started teaching in
midyear.  He would have been replacing Slughorn, right? <snip>

Carol responds:
But why would young snape be applying for a job in, say, October 1979
(BTW, I think that the date was october 31, Harry's presumed
conception date, but that's neither here nor there). If young snape
were really applying for or interested in the perennially open DADA
position at that date, he'd have applied in summer and would have been
teaching if he were hired, which of course he we know he wasn't, since
September 1. Trelawney is clearly applying for a sudden vacancy after
the death or incapacitation of the current Divination teacher. (DD is
even thinking of discontinuing the subject.) This is not a standard
summer job interview such as Snape would have gone through if he were
really interested in applying, or sent to apply, at this early date.
We know nothing about DD turning him down after a first application
for the DADA position because he was too young. And there's still
another twenty-two months or so before he actually starts teaching,
the time between the Prophecy and Harry's birth, when Snape apparently
returned to Dumbledore and became a spy for him, and another thirteen
months after that before he actually began teaching. I conjecture that
LV sent him to apply for the DADA job, perhaps to get him out of the
way, in the summer of 1981, and DD, to protect his spy, gave him the
newly vacated Potions position (Slughorn must have just retired)
instead of the cursed DADA position. (LV can't complain; Snape has his
cover story that DD doesn't want him anywhere near the Dark Arts and
at least Snape is at Hogwarts where LV wants him. No doubt Snape and
DD want him there, too, but for altogether different reasons.)

So to answer your question directly, he couldn't have taken the
Potions position until it became available, and I don't think it was
available during that year when Snape was spying for DE. It's just
possible that teaching at Hogwarts was Snape's or DD's idea, presented
to LV as a chance to spy on DD. LV would of course have wanted him to
apply for the DADA position, but maybe DD and Snape agreed in advance
that he'd be given Potions. I like that scenario, and it would
eliminate any problems created by young Snape's repeatedly being
turned down for the DADA position when he's been told that DD doesn't
want him to be tempted to the Dark side by exposure to the Dark Arts
(not a real hazard of that class unless you're Barty Jr.) but being
given Potions on the third application. 

I think it's most unlikely that Snape was looking for a teaching job
at the time of the Prophecy whether he was a loyal DE or not. Mike
could be right that it's a cover story (at least what DD told
Trelawney after Snape actually became a teacher nearly two years
later). It could be that Trelawney's memory is confused by time and
cooking sherry. Or it could be that JKR's math is so bad that we have
a missing twelve months to account for.

It seems to me most likely that we have:

ca. Oct. 31, 1979: Young Snape, a loyal DE, hears part of the Prophecy
(but see Mike's arguments against this idea)

Soon after July 31, 1980: Young Snape, already conflicted over the
death of Regulus, learns that the Potters and Longbottoms have babies
that could be the Prophecy child and realizes that LV intends to kill
one or both rather tnan waiting to see which child is the greater
threat. He goes to Dumbledore with his tale of remorse and agrees to
spy for him "at great personal risk."

Ca. July 1981: Slughorn resigns, so that both the Potions and DADA
positions are open. Young Snape applies for DADA on LV's orders (with
perhaps a little manipulation by SS and DD thrown in) and is given the
Potions position instead. There is, IMO, no earlier attempt on Snape's
part to get a teaching position, and no interest in teaching at
Hogwarts pre-Prophecy. (What would be LV's motive in sending him there
if he thought himself in no danger from DD or an unborn child or
anyone else?)

Sept. 1, 1981: SS begins teaching, nearly two years after Trelawney.

October 31, 1981: The Potters are killed. Snape is almost certainly at
Hogwarts.

Carol, who agrees with Nikalamati that Snape is DDM and spying for DD
for at least a year before teaching at Hogwarts but also agrees with
Mike that the incompatibility of Trelawney's and DD's versions of the
eavesdropping story requires some explanation beyond details we don't
know yet