The Illustrated Guide to Criminal Law
Chapter 9: At Least You Tried
Attempt pg 24: Mistake Isn’t Impossibility

And Frack over here is a drug dealer. He bought a truckload of kilos from a new supplier who turned out to be a cop.

Actually, he bought a truckload of talcum powder instead of cocaine.

Man signaling an 18-wheeler to “‘mon back!”

Though it was impossible for him to have bought cocaine in this situation—it was only ever going to be talc⁠—Frack is still going to be guilty of attempted possession of cocaine.

What he was trying to do was illegal, and only impossible due to his own mistake as to the facts of the situation. He’s still “dangerous,” and so he’s still guilty of attempt.