I've received a number of attempted rebuttals to that article over the years. The gist of most of them was that all the experts agree that I am wrong, and so it is not necessary to even look at the facts I offerred. While I try to answer such emails politely, I humbly suggest that, even if "all the experts" really did agree, this does not prove it is so. All the experts could be wrong. Of course in real life the experts disagree widely.
But I recently received one email that made a substantive counter-argument. The writer said that if we compare U.S. states that have the death penalty to those that do not, the murder rate in states without a death penalty is actually lower, thus proving that capital punishment not only does not deter, but actually makes matters worse.
This was an interesting claim, so I studied the statistics. I'll ruin any possible surprise ending by telling you my conclusion now: I find the results inconclusive.
I got statistics on murder rate by state from the U.S. Department of Justice Bureau of Justice Statistics. (USDOJBJS for short.) The latest data was for 2001. I got a list of which states had capital punishment as of July 2001 from the Michigan State University Comm Tech Lab and Death Penalty Information Center.
The average murder rate for the 38 states with capital punishment was 5.22 murders per 100,000 people. The average murder rate for the 13 states (including the District of Columbia) without capital punishment was 5.96. So in fact the states with capital punishment had a lower murder rate, but not dramatically lower. Not enough to really prove anything.
The statistics include the District of Columbia as a state. DC has a very high murder rate. If we leave DC out of the average for non-capital punishment states, then their average murder rate is dramatically less, only 3.08. On the one hand you could say it's fair to leave out the one place that has an unusually high number from an average. On the other hand, if we get to arbitrarily leave out all the biggest numbers from the calculation of an average, of course the total will be smaller.
States without capital punishment had murder rates ranging from 1.1 (Vermont and North Dakota) to 40.6 (District of Columbia). States with capital punishment had murder rates ranging from 0.9 (South Dakota) to 11.2 (Louisianna). That is, they completely overlapped.
An opponent of capital punishment could say that this lack of a clear trend is evidence for their case: capital punishment does not deter any more than life imprisonment or whatever other punishment the non-capital punishment states may have. There is no support for the more extreme claim that capital punishment causes more crime (for example, some will argue that such state-sanctioned violence encourages the private variety), but this does support the theory that capital punishment does not deter any more than other penalties.
On the other hand, a supporter of capital punishment could well argue that these statistics are indecisive because they fail to distinguish cause and effect. Just looking at murder rates and existence of capital punishment as a snapshot in time hides any possible trend. If a place has a high murder rate and has capital punishment, is this because capital punishment failed to deter murders, or even caused murders? Or is it because the place's murder rate got so high that the people there finally resorted to capital punishment as a way to fight it?
If this was the only evidence we had, I think I would consider it at least mild evidence against the effectiveness of capital punishment. But it's not the only evidence we have: we also have the evidence of murder rates and changes in laws about capital punishment over time, which, I believe, is more persuasive.
|Without capital punishment|
|With capital punishment|