Judge Posner on the economics of capital punishment

In this remarkable post, Judge Posner explains that there is evidence that the death penalty has a deterrent effect, citing one study which shows that "one execution deters 18 murders," and expressing his view that "[t]he number of people who are executed for a murder they did not commit appears to be vanishingly small," while concluding that "even with the existing, excessive, delay, the recent evidence concerning the deterrent effect of capital punishment provides strong support for resisting the abolition movement."