As an opponent of capital punishment, I think it is ludicrous to say that the concept of serving life without parole is worse than death. As a civilized people we should not commit state sanctioned murder, period. But we should not hesitate to commit violent offenders to life sentences - even if they perceive that as worse than death. The only exception should be if new evidence arises after the verdict that would have had a profound influence on the outcome of the trial, like DNA or the admission (proveable of course) of the crime by another.

Don't kill them but surely severely punish the offender.