PyramidHead
Contributor
They conspired to indiscriminately kill _any_ federal agent that showed up.
If they believe that all mailmen are actually lizardmen in disguise, and then conspire set up deadly traps along the path where mailmen are known to travel (or do something to lure mailmen onto their property with the intent to let the bullets rip once they show up), you think they shouldn't be arrested until the trap goes off and kills a mailman? After all, their intent is to kill a bunch of lizardmen, no?
You've nailed it. If the intent is to kill lizardmen, and killing lizardmen is not a crime, then there can be no charge of conspiracy to kill lizardmen. There can be no charge of conspiracy to kill mailmen because there was no intent to kill mailmen.
A conspiracy charge requires intent to commit a specific crime.
That sets a troubling precedent. Anyone who is accused of conspiracy to commit a specific crime can simply say they thought the potential victims were lizard people. Somehow I doubt you've thought this through.