It cost more of taxpayer's money to send a criminal to death row than it is to keep them in prison for the rest of their life. It's is essentially torture. You're wrong on every point, Andrea. In fact, great lengths are taken for the actual execution to be as painless as possible for the criminal. The proper translation of the Bible's original Hebrew is Thou Shalt Not Murder, and there is a definite distinction between Murder and Execution.
Murder is the actual degrading act, carried out wilfully by an individual.
It's effective when fairly and consistently applied. The study also showed that raising the number of death sentences by one percent would prevent 105 murders. Your point actually could be used to justify executing criminals sooner. And fortunately in fact, there is legislation before the Congress that would limit the endless appeals process murderers now have access to, which would significantly reduce the costs of capital punishment and, more importantly, ease the pain the victims' families have to endure knowing that the criminals continue to breathe while their loved ones do not. Not sure where you're coming from here.