Why DD might not want Snape for DADA job

[pippin_999]

No: HPFGUIDX 94590


> Alice:
> I think the idea was that if Dumbledore gives Snape the DADA 
> position, people would want to know what qualified him for that 
> post in particular.
> 
> I remember hearing someone, somewhere say something 
(yes, 
> very specific, I know) about a JKR interview wherein she 
> mentioned something about Dumbledore believing that the 
> DADA position 'would bring out the worst' in Snape . . .  Does 
> anyone know if any such thing has actually  been said by JKR?

It's the Albert Hall appearance:

http://www.mugglenet.com/jkr-royalalbert.shtml

JACKSON LONG:
Professor Snape has always wanted to be Defence Against the 
Dark Arts teacher. In book five he doesn't get the job. Why doesn't 
Professor Dumbledore let him be the DADA teacher? 

JK Rowling:
That is an excellent question and the reason is
 I have to be 
careful
 not to say too much. However, when Professor 
Dumbledore took Professor Snape onto the staff and Professor 
Snape said he'd like to teach Defence Against the Dark Arts 
please and Professor Dumbledore felt that it might bring out the 
worst in Professor Snape, so Dumbledore said: "I think we'll let 
you teach potions and see how you get along there.

Pippin
"It is dangerous to study too deeply the arts of the Enemy, for 
good or ill." --Elrond (Tolkien, LOTR)