In the case of a murder the victim is just as dead, whatever the state of mind of the perpetrator, but I think there are some differences, but have no idea where to draw the line.
Yes should all be put in jail, mothers who abuse the most sacred trust of a mother to defend her child, yes, throw away the key..
I have the greatest of sympathy, and a great deal of empathy with a mum who snaps one day and throws her baby at the wall to stop it crying, I don't say I condone it, but if you have ever been left alone at a young age with a baby who is a screamer, and no family close by to help, well I'm not sure if I would want that person on death row or in life imprisonment.
Same with a woman who has been trapped in an abusive relationship and suddenly snaps one day? If she fights back when she is being physically attacked, then she may well get off with it, but what about the clever *&^%* who are the emotional batterers, you will never see a scar on them, but we carry those scars deep.
Personally I struggle with the fact that anyone who commits an act of mass murder could be in any way sane, but at the same time can't help thinking that they are so dangerous as to warrant being permanently excluded form society, be it the death penalty or life imprisonment.