Sure, muggs. Pot and alcohol are debatable topics - in this scenario as well. But anyone who shows that they are doing hard drugs is showing a blatant disregard for the law (which cannot be condoned on the road), are likely addicted (which means that they will have problems NOT taking the drug in question while driving), are showing enormous irresponsibility with regard to their own well-being (yes, that's their business - but it shows that they are, on average, not so likely to be concerned with others' well-being), shouldn't be driving. In my town, we have several fatal car wrecks every year (often involving, maiming or killing passers-by) involving kids on drugs. I have a family. I do NOT want kids driving around who do drugs. You can disagree with that. But the vast, vast majority of parents will agree with me. Anything that makes my kids and my wife safer from the predations of others is something that I will strongly consider.
Maybe you should consider locking them up in the house. That would keep them much safer from DUI drivers.
That's fine, at the state level. Why anyone would want the federal government mucking around with the issue of state-issued drivers' licenses is beyond me. Particularly at a time when we're one or two terrorist attacks away from a national drivers' license with an accompanying biometric database.
Good luck.
Did you have a fallout shelter in your back-yard when you were a kid?