This is a slippery slope and bad precedent. We need less Federal intrusion into our lives, not more.The only reason I said Federally mandated is to remove liberal states from NOT following through.
That said, I still agree with you that the death penalty is a proper sentence for certain heinous crimes and is an effective deterrent to some criminals. I wholeheartedly agree that it should be promptly implemented once the justice process (including appeals) has been completed. Sitting on death row for years and years makes little sense.
I disagree, however, that we should create special classes of people for whom sentences should differ. All murder is evil, irrespective of the victim's job or station in life. Killing a homeless prostitute is just as evil as killing a decorated police officer.