It seems to me, and my knowledge is limited to what I've read here, that P1 is P1 is in command has ultimate authority accepts responsibility etc etc....
However, in criminal law there are various offences for incitement.
Am I wrong in thinking then that a possible outcome is that Mr Walker will be deemed responsible for his actions, but those who influenced his decision making might rightly be held accountable in the same way that one can be prosecuted for incitement to (insert your own description)?
If so it doesn't sound unreasonable to me.