Why we should enforce the death penalty

"The State should strive to the same ethics as the individual, but the state has responsibilities that we do not and must sometimes add corrallaries to those ethics to cover those situations. Otherwise it could not function in a way resembling it's goals."

Exactly, the State bears a heavy burden of responsibility to those it governs. All the more reason that its actions be ethical without resorting to the cop-out of situational ethics.

"I think that the lack of deterrent effect is due to the disparity between the ideal of capital punishment and its lack of proper implementation."

Then why do nations that do not embrace this "ideal" still have a lower murder rate per capita than we do?