Death penalty is no different than murder. It’s supposed to be a punishment to show others what happens to you if you commit a severe enough crime. But does that stop people from killing? No. The death penalty sends the wrong message. Why kill someone for killing to show killing is immoral?
Life imprisonment is better, because it gives the convicted the time to reflect about his or her actions, and maybe even be proven innocent when truth is uncovered several years later (which has happened).
Plus, it costs a lot more to administer death penalties than life imprisonment. All that legal shat is a lot of money.
Therefore, life imprisonment is the answer. If someone sentenced to life imprisonment without the possibility of parole, he may kill within the prison, but he could be placed in solitary confinement. 24/7. There he can sit there thinking about his decisions and how he ruined his life, rotting there until his death. On some occassions, he could be let out for a while, or so I’ve heard, so it’s not thaaaaaaat bad. 😛