I think you are a little confused about all this
Putting a dangerous man behind bars is punishment and that is what is needed , it's also justice
Executing someone sets a precedent and I would rather evil people get locked up than capital punishment brought back as it panders to the foaming daily mail and sun readers and one day will lead to innocent people dying at the hands of the state
Lock them up for life
If that makes me a liberal lefty then so be