@DB: I've been that kind of kid (you probably were too though, or you wouldn't have one), and I'm raising one who has a similar attitude about authority. I managed to end up in jail WITHOUT doing drugs or drinking, which is harder than you might think.
You're doing a lot of things right already, and they aren't working. So I want to suggest a different approach that probably will seem unnatural: if he walks around smelling like pot, punish him as severely and swiftly.
Here's why: teenagers are even worse than most people at paying a short-term cost for a long-term benefit. Your son is getting something by being an idiot, and he's decided it's more important than his college admission, student loans, or whatever. So you need create a short-term cost so that he doesn't ruin his life.
The kicker is that you tell him what you're doing. For me, the explanation above would have worked: "you're not being smart enough on your own, so I have to substitute for your brain." I really wanted to be smart, and that would have gotten my attention. Some other kid might benefit from hearing that there's a difference between a good outlaw and a bad outlaw. If he's not a good enough criminal to get away with it, then he needs to follow the rules.
He might listen to you. But at worst--if he's 100% determined to have a pointless confrontation with authority--then at least you can let him have that confrontation with you instead of the judge. It will suck, but it will also help him in the long run.
Assume that he will never ever act like he's listening to you, but be sure that he is. Also, be prepared to follow through on the consequences, which will create an epic fight you'll remember for the rest of your life.