On the legality of death rays
Legal impossibility is a defense to an attempted crime. You cannot be convicted of attempted loitering if there is no law against loitering. This is true even if you thought there was a law against loitering. Nor can you be convicted of attempted trespassing if the place you’re attempting to trespass in is somewhere you had every legal right to be. If you try to sneak into a party that you were invited to in one of those stupid evites you deleted, you haven’t committed a crime, even if you tried to commit one.
Factual impossibility, on the other hand, is not a defense to an attempted crime. The guy who tries to solicit sex from a 14-year-old in an online forum can’t assert the defense that because there were no actual 14-year-olds in the forum his plan wouldn’t have worked. This is true even if it turns out that everybody in the forum was either another predatory or undercover law enforcement. If you try to sell cocaine but end up selling baby powder because somebody screwed you upstream, you’re still guilty of the attempt.
The tiny exception to the factual impossibility rule is inherent impossibility. If it turns out that your plan was so flawed that no reasonable person would consider it a reasonable way to accomplish whatever you are trying to accomplish, you have a defense. An inmate attempted to kill a judge using a voodoo doll. It didn’t work. He was not, however, guilty of attempted murder. If you try to contact a recently-deceased CEO using a Ouija board and buy stock based on what you believe you’ve learned, you’re not really guilty of insider trading. This is all true even if you truly believed it would work.
The logic behind this is less obvious. If you’re trying to kill somebody in the way you consider most efficient, is it less blameworthy to choose voodoo than, say, a handgun? Just because it’s silly doesn’t make it okay. Maybe if somebody tries to kill somebody in an inherently impossible way, we suspect that they weren’t really trying to succeed. Or maybe there’s some mental illness. Or maybe the probability of them ever succeeding at murder is so slim that they simply aren’t dangerous.
So now we have this KKK deathray plot. As the story goes, a couple of guys wanted to build a deathray to sicken or kill people they thought were enemies of Israel. With assistance from an FBI plant, they built something they thought was a death ray. The problem is that a portable death ray of the type described is not a real thing. Maybe something like it could work at a very short distance with access to a huge amount of electricity, provided the target didn’t move around.
I don’t see this as a glorious victory for law enforcement. I’m not sure there’s even a crime here.