Snape and DADA

[Freeman, Louise Margaret]

No: HPFGUIDX 89829

I think that one thing that will need to be explained in future books is why 
Snape was not given the DADA job at the beginning of OotP, when the 
Educational Decree was passed giving the ministry power to appoint a teacher 
*if* Dumbledore could not fill the post.  He says he trusts Snape.  Snape 
had substituted for Lupin in the class back in PoA.  Snape wants the job. 
Dumbledore could therefore have stopped Umbridge from being appointed with 
one stroke of his quill.  Why didn't he do it?

I see only two possibilities 1) He has some, yet to be revealed, reason for 
keeping Snape where he is or 2) He had some reason for wanting Umbridge in 
that position.  He wanted an incompetent teacher in that class the very year 
his prize pupil was to take his OWLS?

I suppose this could lead credence to the "Dumbledore asked Hermione to 
organize the DA theory" but I can't help feeling there is something more.

Louise