This is why we should have the biblical “two or three witnesses” required for a conviction.
Just a drug lab test shouldn’t cut it.
The drug test; a witness; the testimony of someone who says he boasted of being a drug dealer. That’s three witnesses in my book, and if on a jury, I’d vote to convict.
Not on just a drug test.
The problem here is not the “war on drugs.” The problem is the wrongly prosecuted war on drugs. Do it right. Two or three witnesses.
Most of the time your "witnesses" will be people doing so to cop a plea and stay out of jail themselves.