Lester Jackson has this article in TCS Daily titled, "A Death Penalty Red Herring." He attacks the argument that any risk at all of executing an innocent person makes the death penalty unacceptable. Life imprisonment is not zero risk either, though, because some murderers sentenced to life do kill again. Jackson notes that many of the same people are now arguing against life-without-parole sentences, when paroling killers involves a greater risk of death to innocent people. Yet they brush this off as an acceptable risk of a policy they favor even while maintaining that no risk at all is tolerable in a policy they oppose. A more detailed paper with references, "Fact Suppression and the Subversion of Capital Punishment: What Death Penalty Foes on the Supreme Court and in the Media Do Not Want the Public to Know," is on SSRN.