Any advice to stop and aggressive Jack russelle>?

As a trainer I am sure you are aware of how to read her body language. This is a very useful tool.

By the sounds of the context she is having a fear reaction. Do you notice any "warning" signs before she becomes aggressive? And what kind of aggressive behaviour does she perform? Does she growl? does she tr and bite? Does she give a signal that indicates she is uncomfortable then tries to bite?

I'm guessing you also understand the fight or flight concept, this is a great example of fight...she is unable to flee when she is becoming scared or afraid so she is fighting. I'm sure she made attempts to show you this fear but as many people do you probably missed seeing them.

Do you know about desensitization and counter conditioning? This is a great technique that can be used. Also not allow her to become close enough to react is another option

A behaviorist is always a great route to think about.

Aggression is a serious problem - especially if she has gotten you in trouble with the law before. You say you are a trainer but do you have any proof? Certificates? Degrees? Any experience other than home experience? Just because you've worked with her doesn't mean you are a trainer - i work with my aunt's dog on HIS dog aggression, but i don't call myself a trainer.

A true dog trainer would see your dog as what she is - a danger - and would NOT shirk on their duty to train this dog, school or no school. A true dog trainer would also not need to come online for help and would KNOW that there is no quick way to cure aggression.

Get your dog professional help from a certified trainer.

If you are a trainer then you know the answer. There is no 'quick fix' for dog/dog aggression. Either consult with a behaviorist or take the time to work with her.

Add: Click to Calm is a good place to start BTW. I cannot remember the author but if you go to Karen Pryor's clicker training site it should be listed. Dogwise also sells it among other books that are very helpful.

Don't allow her to growl, bark or make any aggressive moves towards strangers. lol Bring brave friends over to slowly socialize your dog. There is no quick fix sorry. It would be great to just snap your finger and the dog would listen. Should have considered the amount of time you would actually get to spend with your dog before you got him.

You say you are a dog trainer, but yet can not work with your own dog?!!