Timing & the Dada position

[Kristen]

No: HPFGUIDX 138880

Denya wrote:  
 All three chapters take place 2 weeks after the end of term.  
(It's just possible that 1 & 2 take place up to a week *after* 3, 
but 
certainly not before).
 At that time, Dumbledore has already injured his hand, recovered 
 the ring horcrux, and made the decision to put Snape in the Dada 
 position (as he's inviting Slughorn back), thus guaranteeing that 
Snape will leave Hogwarts at some point in the coming year.
That timing seems to limit the options considerably vis-à-vis 
Snape being fooled into, or tricked into, or beguiled-by-blue-eyes 
 into the UV.  Dumbledore had *already* decided that this was to be 
Snape's last year.  I can't imagine Dumbledore giving the position 
to Snape without telling him the consequence – that would be too 
painfully dishonest – so Dumbledore and Snape have some kind of 
plan together.  At The Time The UV was made – a plan that would 
result in Snape 
leaving Hogwarts.

Jen wrote:   
I completely agree with you.  I think DD gave Snape the position 
 because he knew he was going to die soon and he always needed Snape 
 with him before.  Another interesting thing is that since Snape was 
 no longer the potions teacher, Harry could continue with his Auror 
 dreams by taking NEWT Potions.  Nice and neat huh?
[snip]

Now Hexicon:
I am starting to come around to the theory that DD knew he was 
dying.  In addition to the points Jen and Denya make, I also think 
DD knew that Snape would not be able to function as a teacher and 
member of the OotP without DD there to continue to vouch for his 
loyalty.   I think DD and Snape would have agreed that the OotP 
members would reject Snape without DD there to provide continued 
assurances.

For example, if DD had died of the ring curse or from the cave 
potion, would the other OotP members agreed to let Snape continue 
his double agent work?    

Assuming that recovering the ring horcrux left DD on borrowed time, 
I think that DD and Snape had reached an agreement that Snape would 
get the DADA position--*before* the UV.  DD knew his death would 
mean an end for both Snape's direct role in the OotP and his 
teaching career.  For this reason, the DADA curse didn't risk any 
additional harm—Snape would have to leave anyway.