What if a defendant is accused of attempting a crime that is factually impossible? For example, suppose that men believed they were raping a drunken, unconscious woman, and were later accused of attempted rape, but defended on the grounds of factual impossibility because the woman was actually dead at the time sexual intercourse took place? Or suppose that a husband intended to poison his wife with strychnine in her coffee, but put sugar in the coffee instead? The “mens rea” or criminal intent was there, but the act itself was not criminal (rape requires a live victim, and murder by poisoning requires the use of poison). States are divided on this, but thirty-seven states have ruled out factual impossibility as a defense to the crime of attempt.
Legal impossibility is different, and is usually acknowledged as a valid defense. If the defendant completes all of his intended acts, but those acts do not fulfill all the required elements of a crime, there could be a successful “impossibility” defense. If Barney (who has poor sight), shoots at a tree stump, thinking it is his neighbor, Ralph, intending to kill him, has he committed an attempt? Many courts would hold that he has not. But the distinction between factual impossibility and legal impossibility is not always clear, and the trend seems to be to punish the intended attempt.