Capital Punishment

What are some of the main justifications used to support the retentionist and abolitionist positions of capital punishment?  Given the economic concerns and error rates associated with capital punishment, do you think it is a practice that can be morally justified?  Why/why not?  Explain your answers in detail.

          Your original post must be 200 words (+/- 10 words; 190 – 210 each or penalty applies).