Sadly, that has been my own experience with this sort of thing. When it escalates, you eventually find yourself in a no-win situation since even if you win, you still "lose" in the hearts-and-minds portion of things. When it is your child, you DO want hearts-and-minds cooperation from those interacting with the child.
When one of the major players poisons that well then they ultimately have "won" because you WILL go away rather than subject your child to a toxic environment.
So yes, deal in facts-- I love Polarbear's way of putting this-- but at the same time, bear in mind that THEIR preferred outcome may be to get rid of the problem while yours is quite different. That said, there are strategic tactics that you will find unthinkable and they will find, er-- useful.
It doesn't mean that they are evil incarnate (though possible given the evidence over the years from the district), just that they have a very different goal than you do.
