A great deal of controversy greeted the recent decision by Gov. George Ryan of

Illinois to commute the death sentences of the 167 prisoners in his state on death row. His decision appalled relatives still grieving over the loss of their loved ones murdered by Illinois’ death row inmates, and it dismayed prosecutors who consider execution a sound way to fight crime.

The governor’s decision has intensified debate over the use of the death penalty by the United States, the only Western nation that still executes convicted murderers. With all due respect to the grief felt by families of murder victims in Illinois and elsewhere, the social science evidence argues overwhelmingly against the use of the death penalty. The case against capital punishment rests on several grounds.

First, the process by which accused murderers end up sentenced to death is rife with error because of incompetent attorneys, prosecutorial and police misconduct, and mistaken testimony.

Gov. Ryan suspended the use of capital punishment three years ago after journalistic investigations exonerated 13 death row inmates in his state.

His continued misgivings over the accuracy of capital punishment led to his mass commutations. Nationally, more than 100 inmates have been freed from death row since the early 1970s after DNA or other evidence raised serious doubts about their guilt.

Second, the application of the death penalty is racially discriminatory. Several studies, including one recently done in Maryland, find that people who murder white victims are much more likely to be charged with a capital crime, and thus to receive the death penalty, than those who murder African-American victims. African Americans accused of murdering white victims are especially likely to be charged with a capital crime. In effect, the criminal justice system values white lives more than African American lives.

Third, the death penalty does not appear to deter homicide. Many studies have been done of this issue, and almost all find no deterrent effect. Most homicides are largely emotional and spontaneous, and potential murderers simply do not take the time to sit down and think whether they want to risk execution. A minority of homicide offenders do plan their crimes and kill in cold blood, but the fact that they are so willing to do so indicates they are not likely to be deterred by possible execution. Some studies even find that capital punishment may increase the number of homicides, in what has been called a “brutalization” effect.

Fourth, execution is much more expensive than life imprisonment. Capital cases are very time-consuming and expensive. Because almost all capital defendants are poor, the state pays for their legal expenses, including trial and appeal. These expenses amount to between $2 million and $3 million by the time a person is executed. In contrast, the cost of life imprisonment is about $1 million in current dollars, assuming 40 years in prison and $25,000 in annual incarceration costs per capital defendant. Thus, each capital case costs about $1 million to $2 million more than a non-capital case involving life imprisonment. If the approximately 3,700 people on death row nationally were all eventually executed, the total extra cost to their states would be between $3.7 billion and $7.4 billion.

The evidence just cited does not address the morality of the death penalty: Is execution a justifiable act of retribution against someone who murders or, instead, an immoral act for a civilized nation? This question is best left to philosophers and theologians, not social scientists. The morality of execution notwithstanding, the fact remains that capital punishment is a failed social policy. It is prone to error, it is racially discriminatory, it does not deter homicide, and it is incredibly expensive.

As a failed policy, capital punishment should be abolished. Maine and 11 other states do not have the death penalty; the rest of the nation should follow their lead and eliminate it. Doing so would finally bring the United States in line with the rest of the world’s democracies.

Steven E. Barkan is a professor in the University of Maine Department of Sociology.