state sanctioned murder is still murder.
The death penalty does not fulfill it's supposed role as a general deterrent. It does not send a good message to society in general either, that violence can only be solved by violence.
I am always surprised when a conservative tells me they are for the death penalty. I am pretty far to the left, and I don't trust the government to deliver mail properly, so there is no way in hell I want them to have the power to kill someone.