This is a toughie, but I’m on your side, Bear. It sucks that our litigious society makes you have to consider the other side of the issue, but I think you were covered here.
The student was being disciplined just by being there in the office, and was to see the AP later. There was no real point in you horning in on that. In fact, I wouldn’t be surprised if the AP would have complained if you had taken a larger role in the process.
What you did do, however, was make it clear to this student that she couldn’t fool you. That probably had the greatest impact. She might have come to the office thinking that if she played it cool, no one could make her confess. After talking with you, she now knows that she can’t get away with it again. I expect the principal will be calling a deputy next time, now that he knows what can be learned from the nastagnus test.
After showing her that she can’t fake her way through, you trusted her to handle it. That also had a great impact on her. A lot of today’s adults forget that the best way to instill responsibility in a teenager is to treat them as adults. In this case, you didn’t let her totally off the hook (You couldn’t, since she was on the way to the AP.), but you let her know that you trust her to take her school life seriously.
Let me tell you a little story from my high school days. I was a nerd, so I didn’t get into much trouble myself. But my brother and his two best friends were a bit more independant-minded. They were like your cheerleader, in that they tended to break a few rules while getting good grades and being involved in the school activities. The principal was smart enough to see they were of this type.
One day, some of the real troublemakers were up to no good. I don’t recall what it was, but it was disruptive. Our principal called my brother and his friends in to his office. He explained that these kids were making it hard to run the school, and that he needed them to stop. But he also knew that being yelled at or disciplined by the principal wouldn’t have too much effect. So, he asked these three boys to help. He felt that they were smart enough to want to learn, and to know that these troublemakers are making that harder. He also felt that the troublemakers would listen to their peers.
My brother and his friends went to the troublemakers and asked them to knock it off. The problems stopped, and they felt more like responsible people. They also had a grudging respect for the principal, because he understood the kids so well.
Eighteen years later, my brother and one of his friends are both police officers. The other is vice president at a fairly large corporation.
My point is, that you can get a lot of response out of some kids by giving them slack, letting them know that you think they are smart enough to do the right thing. Obviously, you can’t do that with every kid, but I think you did right with this one.
On another point, if the principal thinks you screwed up by not reporting what you knew, I hope he ripped into the AP that left her sitting for so long. If he wanted to catch her drunk, letting her sober up for the better part of an hour isn’t the way to go about it. If this stuff is so important to him, he should make policy to make that happen. Such as, meet with students as soon as possible, and call in a deputy in these cases. Not that I think that would be the right policy, just that anything else is a little inconsistant on the principal’s part.