My one big question here is why is everyone just assuming
that Arthur was an aggressive dog? The orginal problem was
posted as a aggression problem with Charlie, not Arthur.

http://petoftheday.com/talk/showthre...hlight=charlie

Some people responded with advice and the subject was just
dropped. No follow up on trainers help or anything else. I do agree that Arthur had just had enough of Charlie's harrassment.

When problems like this crop up I believe it's up to the folks
involved to actively work to find a solution before it ever reaches
a crisis stage. I keep thinking what will become of Anna now that
she might probably driven to behave the same way Arthur was
forced to do. So sad.