are you serious? why would someone be distracted by their friend's taking drugs? get the fuck over it...seriously. unless someone is seriously putting their life in danger (which is almost never the case), it shouldnt matter what they're doing. if you dont want to be involved, either accept it or get some new friends?
the point is drug use is illegal? well, if you're saying that to help him with his debate, then ok, thats a good thing to bring up. but if you're serious, like the first half of your post seemed to be, then, no. first of all, prohibition doesnt work. second, just because someone is doing something illegal, doesnt mean everyone should be watched closely for it and everyone should suffer.
back to the original thread. you could use her point about saying drug use is illegal. and while at school, the school is responsible for the students, and if it feels as tho drugs are becoming a problem, they should be allowed to do the tests simply because drugs are illegal. especially in the case of minors.
kinda sorta with that ^ point. school's are drug free zones, so just because you dont have possession, you're still bringing them into the school by doing them because obviously people talk and such.
you could say with all the drugs used in sports these days, its a good idea to send a strong message at a young age that drugs aren't allowed. sure, theres the kids that dont play sports, but thats a big chunk that you could test. this could prevent drug use later in life?
i dont think they should test, but thats just me. these^ are just to help you out