Who's going to betray the Order?

[acoteucla]

No: HPFGUIDX 75704

I think most people would agree that there is going to be a major 
betrayal (most likely in book 7).  Assumedly it will be someone we 
trust enough that it will be a huge shock.  I'm hoping to stimulate 
some discussion on who it will be.  Here are my thoughts on the 
various suspects.  Make sure to mention any likely suspects I might 
have missed.

Ron:
There is a lot of talk that Ron will betray Harry.  He certainly 
qualifies as a major, shocking betrayal.  Personally, I've seen 
little to no evidence that Ron is capable of such a betrayal.  Due to 
the support for this theory, though, I'll list it as a possibility.

Percy:
He certainly seems like a likely candidate to betray everyone, but 
first he'd have to make amends with his family.  Even if he does 
that, it wouldn't be overly surprising to find out that Percy betrays 
them.  So he doesn't qualify as a "shocking" betrayal.  I would 
expect the betrayer to be someone we trust, not a git like Percy.

The other Weasleys:
I've personally seen no evidence that any of the other Weasley's 
might turn spy.  But speak up if you're in favor of ESE!Molly, or 
something like that.

Lupin:
My favored choice: he's sympathetic, seemingly very kind, and has 
Dumbledore's & Harry's trust.  There's also some suspicious details 
about the scene at the end of book 3 which are explained if Lupin is 
evil.  Of course, there's also some hard stuff to explain away (like, 
why does he prevent Harry from going through the veil?)

Snape:
This would certainly be a major and shocking betrayal.  I personally 
don't buy it, but I know that ESE!Snape has it's supporters.

Tonks:
Wouldn't be overly shocking, given her limited screen-time.  However, 
interpreted in a certain light, Tonks' claim to have just become an 
auror could clash with McGonagall's assertion that there have been no 
new auror's recently.  Also, Tonks' metamorph ability is just begging 
to be used.

Mundungus:
Maybe he intentionally left his watch right before the Dementors came 
to get Harry?  This betrayal wouldn't be overly shocking either, 
though.

The other Order members:
These other guys seem to be either extraordinarily unlikely (like 
Dumbledore or Hagrid), or too minor a character to be shocking at 
all.  Again, speak up if you're in favor of ESE!McGonagall or 
something like that.

Seamus:
Sure, why not?

Cho:
This, I would love to see :-)

Harry:
*cough* next choice, please.

The other students:
Anyone in favor of ESE!Hermione or ESE!Luna?