Allow me to preface this by saying that I am not a supporter of the death penalty.
Nevertheless, the "the death penalty is bad because it's more expensive than life in prison" argument seems to me to be extraordinarily weak, since it's essentially a milder version of the
Charles Taylor pitch. It's not that the death penalty is inherently expensive - way back when the only costs were a hangman and a piece of rope. Rather, it's death penalty opponents saying that "if you try to apply the death penalty we will finance endless frivolous appeals and get our like-minded judges to let them drag out interminably in order to
make it more expensive than life in prison."