The Death Penalty, Is it Good Or Bad?

I am and always have been the pro death penalty, however, even though I am pro death penalty, I probably would not be willing to pull the switch or push the button. I do not think that this makes me a hypocrit. Please bear with me while I explain.
As I stated, I am pro death penalty. I am not, however, pro death penalty as an act of revenge or retribution. I believe that in certain instances it does act as a deterrent to crime and can save lives. I realize that some people have no respect for life, not even their own, and would commit violent acts no matter what the penalty. I also realize that some people get caught up in the heat of passion and don't think about the consequences of their actions. There are people, however, that do care about themselves even if they don't care about others and the only thing that stops them from commiting certain crimes is the idea that they might, if caught, be executed. They may not have a conscience, they may not care about the harm they do others, they may not believe in or care about an afterlife but, they do care about their own skin and they want to protect themselves from harm. Many of these people don't care if they go to prison but they do want to live. Many of them while in prison would murder other prisoners or guards but don't because they don't want to turn their life sentence into a death sentence. If the death penalty saves even one or two innocent lives, I believe that it is worth having.
On the other hand, I am not omnipotent, I don't know everything. I realize that some, or even many, innocent people may have been executed by mistake. However, I believe that many more innocent lives have been saved than lost because of the death penalty.
I also know that the death penalty can be more expensive and cost the taxpayers more than incarcerating someone for life. However, if it saves innocent lives, it is worth the extra cost. Additionally, if the death penalty process was streamlined the cost would be far less.
Having stated the foregoing, I still probably would not be willing to pull the switch or press the button. Luckily for me there are others that for some reason, either out of a sense of duty or for some other reason, are able to and will do the deed.
My problem stems from uncertainty. Is there a God (I hope so.), and if there is a God, did he send down the Ten Commandments? If God did, what did God mean by "thou shalt not commit murder" (Note: It is not "thou shalt not kill" it is "thou shalt not commit murder", check with a theologian.)? Is it murder to execute a murderer or is it carrying out God's will by protecting other people. Would I loose my soul and an afterlife by executing a murderer. I would be willing to loose my soul in order to protect my love ones by killing someone who threatened them, or to go to war in order to protect my family and country but I might be too selfish to be willing to loose my soul by carrying out a legal execution. I just thought of something, could this selfishness cost me my soul? Oh boy, one more thing to ponder. I either don't have enough faith or I have too much faith. I can't be sure which it is, but I assume that it is not enough faith, because, if I truly believed in a just God, I would be able to trust in him and leave it in his hands.
Finally, I say I probably would not be willing to push the button. I say probably because you never know what you would do when it comes right down to it. I don't think I'd have the guts, however, if there was no one else to do it, who knows?