It sounds like a horrible idea really. Charging someone with a crime they didn’t commit, no matter how much evidence there is they didn’t do it. It seems like it would preclude all possibility of defense too, since proving that you didn’t do it doesn’t get you a damn thing. That doesn’t sound like justice to me.
I agree, but maybe the sentence severity would take that into account?
“no matter how much evidence there is they didn’t do it” is naive. The idea is that you shouldn’t have conspired to commit a crime in the first place.
Going back to the earlier chapters on the mens-rea scale – it’s pretty easy to imagine conspiracies having something similar, but it basically starts at Reckless and quickly scales to Knowing. If I commit/plan a robbery, and someone gets hurt or killed in the process by a conspirator, I may not have intended that (I wanted easy cash, not a fight!), and I may not have done that, but maybe I shouldn’t have been planning an action likely to devolve into violence in the first place? It gets worse if, say, I hire someone I know has violent tendencies, or equip them with weaponry (even with an intent not to use it).
If a crime is *truly* disconnected from the original conspiracy – e.g. the ATM robbery in the example story – then sure, a prosecutor trying to slip in conspiracy is on shaky grounds. But in many other cases, it’s hardly unjust.