Somewhere, I ran across the following story:
Fred was the most hated person in the Foreign Legion. Everyone wanted him dead. One day, Fred was assigned to go on a mission alone in the middle of the desert. At midnight the night before, Alex put poison in Fred’s canteen. An hour later, unaware of this, Bert poured out the contents of Fred’s canteen and filled it with sand. An hour later, also unaware of what the others were doing, Charlie poked a hole in the bottom of the canteen, so that the contents would pour out. Thus, poor despised Fred died in the desert the next day.
So the question is: who, if anyone, is guilty of killing Fred? It’s tempting to say Charlie, simply because he came last, but really, all three of Alex, Bert, and Charlie tried to kill Fred, and took steps to kill him. The only reason to let Alex off the hook is that Bert’s approach undid what Alex did, and Charlie’s preferred method undid Bert’s. But remove any one, or any two of them, and Fred still winds up dead. At best, Alex and Bert would be guilty only of attempted murder.
What if they had all poisoned the canteen? It would be a lot easier to argue that all of them are to blame. If only Alex were put on trial, it would be fairly easy to secure a conviction. And even if Bert’s and Charlie’s actions came to light later, few people would feel that Alex was wrongly convicted. Same for the other two.
The reason I bring this up is that the defense in Derek Chauvin’s trial for the murder of George Floyd has claimed that drugs in Floyd’s system are to blame for his death, not the fact that Chauvin knelt on Floyd’s neck for over eight minutes.
I trust you see the point: even if Floyd was incapacitated or in diminished health because of drugs, or had a heart attack, or something like that, what Chauvin did could have killed pretty much anyone. If his knee wasn’t the cause of death, that’s only on a technicality. If the situation were repeated, there is no reason to think that a similar technicality would let him off the hook, and every reason to believe that his actions would be similar.