For some, I might propose, the prospect of rotting in jail for 25+ years might be a greater deterrent than a quick jab in the arm and its all over.
A lot of people here in Connecticut who were in favor of the death penalty for Steven Hayes changed their minds once it came out that he smiled when the jury recommended it. He had told his attorneys that he was terrified of spending his life in prison, especially due to being a target for other inmates, and he wanted to die as quickly as possible. So, in an effort to punish him, the jury gave him exactly what he wanted. Something to think about.