If you get blood tested, you might be able to find out if you were drugged. That'd basically exonerate you, depending on exactly what's in the law. It's not your fault if you were unwittingly given a mind-altering substance.

However, if you weren't drugged, then you can hardly blame this on booze, since you chose to get plastered to the point where you didn't have any control over your actions. The liquor laws do exist for a reason, and it's not just "to stop people having fun".