So to recap, the study purports to find a deterrent effect in the immediate aftermath, even if no one knows about the execution, and it mostly "deters" people from other kinds of murders.
They found that many earlier studies had vastly overestimated the effect, but the number of murders did go down in the short-term aftermath of executions.
Based on two different statistical models, they found the effect in the months after each execution to be a reduction of between 0.5 to 2.5 homicides.
That may not sound like much, but as the authors note, “even the estimated .5 deterrent per execution yields an estimated reduction in the expected numbers of monthly homicides of 5 to 10 during the subsequent 12 months, which is substantial.”
I'm sure this isn't the last word on the issue. That's no mystery. Here's the mystery:
This study and previous ones show no correlation between the amount of publicity executions receive and their deterrent effect.
“We have no theory on that,” Teske said on Friday. After a few more questions, he said, “I hear your frustration. If I wasn't working with one of the top guys in the nation, my confidence would be shaken.”
One other mystery: The study shows, as other studies have, more impact on the kinds of murders that don't qualify for the death penalty than on those that do.
In my experience, the death penalty's deterrent effect is a lot like the existence of God - you believe in it if you need to believe in it, but it cannot be proven or disproven by available data in a way that will satisfy the culture warriors on either side.
Let's face it: If the death penalty seriously deterred, then Texas as the nation's execution leader would surely see the greatest reduction in murder rates nationally. But our murder rates, though declining, remain above the national average (in line with other southern states), so clearly other factors are more determinative.
In general, people believe harsh penalties deter misbehavior more than they do. (As Mark Kleiman's new book points out, certainty and immediacy of punishment are much more important.) After the Texas Legislature made stealing even the smallest amount of scrap metal a felony, total thefts skyrocketed thanks to the rising cost of copper. The resulting impact on crime from increased penalties is at best (to use a word I learned from Justice Alito this week) evanescent.
It doesn't really matter if the death penalty deters or not because its greatest importance is as a symbol, pro and con. Neither side will budge an inch no matter what this or that new study might find, and the broader public seems profoundly unmoved, as well - at least until the day an individual voter must enter a jury box and decide an individual case.
The Gallup poll question generally cited to show public support for capital punishment asks, "Are you in favor of the death penalty for a person convicted of murder." Here is the data on that question over time - most recently, 65% of the public said they agreed that people convicted of murder should get the death penalty.
But that question comes at respondents completely detached from reality. In Texas, which is the acknowledged national death penalty leader, in FY 2007 we sent just 14 murderers to death row, while a whopping 1,078 entered TDCJ that year based on homicide charges. Even in the Lone Star State, the vast, overwhelming majority of murderers are not sentenced to death. When the question is presented to them directly, Texas' "death-qualified" juries usually don't impose the sentence. In 2007, out of 51 cases where defendants were convicted of capital murder, in 37 of them juries gave sentences of life without parole.
Juries are selected from voter rolls so there's a disconnect when 65% tell pollsters murderers should die but 72.5% of Texas capital juries fail to impose a death sentence. What that means, I think, is that the issue is more complex than it's presented by pollsters and people are smarter than such ill-informed, misleading questions can measure. When confronted with the real-world issues that surround killing by the state, juries balk more often than not, even in Texas.
I'm not inherently against the death penalty, though I certainly share fears that our sloppy justice system might convict and kill an innocent person. (Besides Timothy Cole, I mean.) I think death is an appropriate sentence for lifers who commit murders in prison - tacking on more years simply isn't a meaningful deterrent in that setting. Make me philosopher-king, and I also think it should be used only in cases (which is most of them) where the identity of the killer is not in dispute. At the same time, the cause of "saving" death-row offenders from a fate that awaits us all, when life without parole is the alternative, frankly fails to motivate me.
Perhaps there is some vanishingly small, short-term deterrent effect to the death penalty. Like the existence of a God that created man in His own image, I doubt it but won't rule it out. But in its current form, the death penalty is a political boondoggle and distraction involving a miniscule number of cases - a costly sideshow carnival act of the first order that distracts from more important discussions. Any legitimate cost-benefit analysis would find death-penalty deterrence doesn't measure up compared to underfunded but less-expensive programs that would save more lives and do more to reduce crime and deaths.
Death penalty cases easily can cost the county bringing them upward of $1 or $2 million each before they're said and done. (It'd be easier to justly complain about that cost if Texas didn't screw up so many cases - it literally doesn't matter if the judge slept with the prosecutor, our Court of Criminal Appeals will sign off on the execution.)
Would that money do more to promote safety if, for example, it were used to reduce community supervision caseloads or pay for ignition interlock devices on the cars of recidivist drunks? Almost certainly. But the details of misdemeanor probation conditions are boring things to debate compared to the death penalty, where everyone gets to claim the moral high ground, look down their noses, sneer, and accuse one another of "bias." That's all a lot more fun (and politically useful, one supposes) than prioritizing criminal justice spending on programs that demonstrably reduce deaths and crime.