Throw Away the Key!
Personally, I am uncomfortable with the death penalty. But if he lives, he will likely be interviewed many times over his remaining years, continuing his "celebrity" status. Timothy McVeigh, the Oklahoma City bomber was executed in 2001, only about six years after that horrible act. At least he's no longer available for the press and sympathizers, and he has apparently not been missed. (His partner Terry Nichols received a life sentence.)
I think we could compromise with a maximum security, minimal contact prison reserved exclusively for such cases. You walk in the front door, but a coffin is the only way out. Press contact is all but prohibited. There is no law library, no exercise gym, no movies, no TV except alternating half hours of Chris Matthews and Judy Woodruff. You can listen to the radio if you behave, read some donated books. The food is somewhere between military field rations and soylent green, nutritious to a fault. No ice. No air conditioning.
There's no aspirin, no surgery, no cancer treatments, and no dental care. Infections are dressed and anti-biotics used only as necessary to keep the facility disinfected. You won't be executed, but chances are you'll not live as long as you otherwise might have. If your appendix goes, too bad. You chose not to live as a civilized man, and civilization has now decided to live without you.
So if you commit murder, you get maybe five years from the date of the crime, then you are sent to what I hope you'll consider to be a hell hole. If not, we'll add Christiane Amanpour to your TV lineup.