Natural consequences.
You put enough mind altering substance into your body and that is what will happen.
Having to deal with someone right now who bought into the "it's just an herb" so it is harmless. Maybe, although I would not bet on it, but when you are high your brain is not exactly working at peak capacity.
“You put enough mind altering substance into your body and that is what will happen.”
Why should anyone think deep-red Oklahoma will put “enough” marijuana into their bodies?
I'm not sure anything is "harmless" - certainly alcohol, tobacco, and marijuana are not. It can only make the message of marijuana's downside more readily received if we stop ending the message with "... and that's why we'll throw you in jail for using it."