Execution is not murder by its very definition. Execution is a legal form of punishment for certain crimes in certain states. It is not murder even if an innocent man is executed; it is a tragedy and a failure of our justice system.
The death penalty should be used rarely and only with the most heinous of crimes, where guilt has been established by myriad corroborated physical evidence beyond all reasonable doubt. It should never be used in a purely circumstantial case, it should never be used as a legal lever to coerce plea bargained confessions or testimony against another, it should never be used as a political tool to enhance a prosecutor or D.A.'s reputation. And because it is used 95% of the time for all the cases it should not be used on, it has become a travesty and has lost credence when used in those rare cases where it is appropriate and deserved.
BTW, the death penalty is an important issue to debate. I'm disappointed that it was used as a link to abortion.