Twenty years ago, Justice Harry Blackmun rejected the death penalty by announcing that he would no longer “tinker with the machinery of death.” Similarly, the abolition of the Illinois death penalty three years ago spared state courts from their own endless tinkering. Yet the death penalty is still legal in 32 states and in the federal system. And a recent story from Iran reminded me of why we still need to think and talk about it. A man identified only as Alireza M. was found guilty of smuggling drugs …