In the case of capital punishment (which seems to be mandated in
Genesis 9:6), some human being has to actually flip the switch to the electric chair.
Is the flip switcher guy now guilty of murder? Or is he lawfully "bearing the sword" of the state as in
Romans 13? The same logic can be applied to the military, police, FBI, etc.
However, this is still a sticky issue. For example, were the Nazi soldiers innocent when they obeyed orders to slaughter Jews in the Holocaust? This is where the "just war theory" comes into play.