Locking them up for life is only cheaper because nobody will dare control the defense bar's racket.   And for the record, I'm not a death penalty advocate; I used the same tools and rules to take people's jobs and did it before skilled arbitrators and ALJs, not twelve morons with driver's licenses, and I won way to many I should have lost and lost too many I should have won to have much faith in the adversarial system to do anything irrevocable..