P1: Murder is immoral.
P2: Capital punishment is murder.
P3: Therefore capital punishment is immoral.
P1: It is immoral to execute even one innocent person.
P2: Some convicted criminals are innocent.
P3: It is therefore immoral to execute convicted criminals.
"It's always reassuring to find you've made the right enemies." -- William J. Donovan
Comparing abortion to the death penalty is entirely erroneous. In order for abortion to be illegal regardless if the unborn is deemed a person or not you must accept the premise that it is ok to force someone to serve someone else. Furthermore, since we can assume the government is not involved directly we can safely say the government is not killing human beings. Of course, due to current involvement in the matter we can not say the government is not involved in the killing of human beings indirectly. The death penalty doesn't involve matters of servitude, but is simply the government killing their own citizens for breaking laws they deem permit the punishment of death.
As others have stated previously, the man both raped and murdered a pregnant woman. I'm not entirely distraught at the prospect of his death being slightly more painful than the usual treatment.