Possible reason for giving Snape the job

[Schumar1999]

No: HPFGUIDX 135495

Kelly says:
> My real question is why did Jo make Snape the
> DADA teacher? What was her reason for writing the story this
way?
> After all, she could have had Harry scrape an O in Potions.


AA says: Although this is neither a direct nor complete answer, we do
know that Snape could _not_ possibly be Potions master while Harry
was discovering the wonders of the HBP textbook, for obvious
reasons.

Marianne S: One thing I find VERY clear about Harry's work using the 
HBP textbook is that if Snape had ever given him a chance.. if he had
 treated him impartially in class and not taunted and maligned Harry 
right from the start (I'm still resentful about Snape and Harry's first 
potions lesson back in PS/SS and almost every potions class since)
 
Harry most likely could have followed Snape's directions to be as
uccessful potion maker. In fact, had Harry gotten unprejudiced 
treatment from the start, he might have even been able to gain some 
Lily-like intuition in the art of Potions. His ability to get an E despite 
Snape's horrible treatment of him, plus the fact that we saw that Harry 
was able to follow Snape's directions back in OotP at the time when 
Snape was pretty much leaving Harry alone after seeing "Snape's 
Worst Memory." Harry only lost out on getting a good mark because 
of Malfoy's interference and Hermione's "help"
 though I doubt 
Snape would have given him a fair shake Regardless. 

From a literary standpoint, I think that it was right for JKR to make Snape 
the DADA teacher. 1) It foreshadowed that Snape would most likely be 
leaving Hogwarts (even the students discussed this point). 2) It made 
Snape available to teach Harry important things about DADA that 
possibly no one else could have, without having to relive the fiasco 
of private tutoring. (Like AA, I would have loved to be in that class
 
though still not as much as Lupin's). 3) We needed to get Slughorn there 
to reveal the memory about the horcruxes AND to show Harry what 
was possible in potions with a fair and just teacher (even if this teacher 
was more the HBP than Slughorn himself) and 4)I think it was very wise 
for Harry to learn a great deal from HBP and even regard him as almost 
a "friend," finding a way to defend and trust him even after Sectumsempra 
(like how Dumbledore always defends and trusts Snape as well). 
Sectumsempra itself was a very wise device because it allowed us to see
 that Harry has a conscience, even against his enemies, and I think it is 
important that we never see Snape himself use a hex this evil against anybody.
even when he clearly had the chance. 

Marianne S.