Unless he didn't know about the death penalty before he started killing people, the death penalty as a detterant failed miserably.If it worked then every state with the death penalty would have lower murder rates.
Not when there's basically no chance of even getting the death penalty, even in those states.
In general, the death penalty exists in name only. 1174 people have been executed in the past 33 years.... which means of all the death penalty states, most of them have many years in the past 33 during which they haven't executed anyone at all... so you can't really say that having the death penalty has had an effect on the murder rates there one way or the other.
You can only tell the effect when a significant number of executions happen in a given state in a given year.
Example. Kansas is a death penalty state. Kansas has not executed anyone in the past 33 years.
Kansas has lower murder rates than Michigan, Alaska, New Jersey, and New York.... all four non-death penalty states.
You know what other states has a lower murder rate than Michigan and Alaska? Texas, California, Virginia, Oklahoma, Ohio... states most likely to execute people in any given year.
Another state more likely to execute people... Florida. And from 96 to 07, Florida has constantly had a lower murder rate than Michigan, a non death penalty state.
Heck... Utah was the first to start executing people in 1977... by a rather violent method no less.... firing squad. you'd figure they'd have a tremendously high murder rate, if the death penalty has the opposite effect of a deterrent... but no... Utah has the 11th lowest murder rate in the nation. There are 8 non-death penalty states with higher murder rates than Utah.
Before you start telling people whether or not it works, it needs to be given a chance to work. Let every state that has the death penalty execute more than 50% of those convicted of a capital offense every year.... and then come back and tell me whether it's a deterrent or not.