Drugs are both “illegal” and a form of “terrorism”.
Amendments are done too often already...
I can name several that should be repealed. The very last thing we need is more amendments.
Then pass an Amendment. If alcohol required one, so should anything else. Too much of our Constitution has been subverted just to keep the current multi-trillion dollar boondoggle "war on drugs" alive. No-knock raids, wire tapping, warrentless searches, victimless crimes... All in the name of some prudish need to tell others what to do. As has been pointed out, they can't even keep drugs out of maximum security prisons. Enforcing this on 300 plus million people would be feasible and affordable how again?
Let 'em die. Help them die through defensive use of deadly force if in their drug induced stupor they decide to attack you or yours. Setting up a Nanny State to protect you only makes you, and all those around you, subject to compounding abuses that eventually destroy everything those before you fought and died for.