Another thing worth mentioning is how a punishment is enforce plays a huge role on how much of a deterence it is. I was reading about some head of the Mexican Mafia who was still running the show behind bars. Everybody did exactly what he said. Why? Because it you didn't you get beaten badly or killed. And they knew he didn't dick around. No one questioned questioned Saddam Hussein and he kept his savage people in order because he ruled with an iron fist. A couple of months ago I was listening to an interview with a journalist who traveled throughout the world. He was asked what, in his opinion, was the safest country. He said without a doubt it was the countries with a police state. Countries like North Korea, China, the old Soviet Union. He said that he once lost his wallet full of money while he was in Libya. The next day he retraced his steps and found it lying there in the middle of the sidewalk untouched. He said those people live in fear and they don't dare fall out of line. They feel they are watched constantly as their are snitches everywhere and feel there's always traps out there to test them.
Punishment is a deterrent. Just remember how it was growing up and how you didn't do certain things because your daddy would whip you. Well, at least they did in my day. Death, by it's finality, is the ultimate deterrent. It just depend how it is applied.