I believe that the death penalty CAN be effective, but only if it isn't abused. As in, sometimes people do need to be punished greatly if they've done something awful, but what if somebody innocent gets the death penalty for doing nothing against the law?
That's why, in my opinion, the death penalty sometimes needs to be implemented for a working society and it's people to show other criminals and theifs "how they roll". But, if it used to much, the let's say, democratic system becomes a dictatorship, which will lead people to rebellions and colaps of the state, because, eventually, it will run out of people to execute.
