My opinion of death penalty is that at the volume it is applied now, it is near meaningless and can just as well be abolished. If it solved the question of "cleaning the society at acceptable economic costs" (it's not practical to just lock up millions upon millions of people for life), it could make sense - then could be a true solution to crime. Today people blatantly sell stolen items in the street asking "so you are going to jail us ALL huh?" and they are right - that can't be done so they are safe doing it. But, bullets are cheap.
But today, death penalty is just an annoyance and does little except pushing society further and further to the extreme left.