Forty years ago this week, the U.S. Supreme Court in Furman v. Georgia struck down the death penalty on the ground that it was applied in an arbitrary manner. Four years later, the Supreme Court accepted the constitutionality of “new and improved” death penalty statutes that were supposed to eliminate the defects condemned in Furman. In bringing back the death penalty in 1976, the Court also cited studies suggesting that executions save lives.

Four decades later, there is plenty of evidence that the death penalty continues to be applied in an unfair manner and not a shred of evidence that the death penalty deters.

This is not to say that death penalty supporters have not repeatedly offered studies claiming to show deterrence. Indeed, such widely-trumpeted but wholly unreliable studies have appeared at critical moments to try to stem the waning support for the death penalty.

But all of these studies have now been properly interred. Recently, the prestigious National Research Council, affiliated with the National Academy of Sciences, concluded that studies claiming that the death penalty has a deterrent effect on murder rates were “fundamentally flawed” and should not be used when making policy decisions about the death penalty.