O'Malley, a Catholic who has cited religious opposition to the death penalty in the past, is now arguing that capital cases cost three times as much as homicide cases where the death penalty is not sought. "We can't afford that," he said, "when there are better and cheaper ways to reduce crime."
Lawmakers in Colorado, Kansas, Montana, Nebraska, and New Hampshire have made the same argument in recent months as they push bills seeking to repeal the death penalty.
And last month, New Mexico became the most recent state to abolish the death penalty. Its Governor, Bill Richardson, who signed the measure despite having been a longtime supporter of capital punishment, said that cost was a factor in his decision.
Death-penalty opponents, who have long focused on questions of morality or justice, say they are pleased to have allies raising the economic argument.
Thirty-five states have the death penalty on their books; 15 now ban it, including New Mexico and New Jersey, which abolished it in 2007.
Support among Americans for the death penalty seems to be fading. After years in which solid majorities supported capital punishment, a recent Gallup poll showed the nation about equally divided when life without parole is offered as an alternative.
The number of executions each year in the U.S. has dropped by more than half since its peak of 98 in 1999, to 37 in 2008. At the same time, the death penalty has come under increasing scrutiny. Exonerations of death-row inmates, based on DNA and other evidence, have led to charges that the death penalty is too severeand finala punishment.
The courts also have narrowed the death penalty's scope. In 2002, the Supreme Court ruled that executing the mentally retarded violates the 8th Amendment's ban on cruel and unusual punishment. In 2005, the Court decided in Roper v. Simmons that it was unconstitutional to execute anyone for crimes committed as a juvenile (defined as under the age of 18).
And now, economic realities are forcing even some supporters of the death penalty to rethink their positions. A 2008 study of Maryland by the Urban Institute concluded that because of appeals, it costs almost $2 million more for the state to put someone to death than it costs to put a person in prison, even for a life sentence.
Long Trials, More Lawyers
Capital cases are expensive because the trials tend to take longer, they typically require more lawyers and more-costly expert witnesses, and they are far more likely to lead to multiple appeals. Furthermore, in many states, death-row inmates often spend decades in prison before their appeals are exhausted.
But it doesn't have to be that way, says Kent Scheidegger of the Criminal Justice Legal Foundation, a victim's rights group.
"The cost of keeping a person on death row for 20 years is not a cost of the death penalty; it's a cost of the obstruction of the death penalty," Scheidegger says. "If cases went from trial to execution in five years, like they do in Virginia, that other 15 years of cost would be gone."
On average, it costs $23,000 a year to keep someone in prison, according to the Bureau of Justice Statistics. That number varies widely, depending on the state and the level of security of the prison. Death rows are among the most costly.
Scheidegger calls the anticipated savings from abolishing the death penalty a mirage. He says that having the death penalty on the books means prosecutors can offer life sentences in plea bargains and thus avoid trial costs altogether.
Opponents of repealing capital punishment also say it is short-sighted and will result in more crime and greater costs to states down the road. As police departments face budget cuts, the role of the death penalty in deterring crime is more important than ever, they say.
Scott Shellenberger, a prosecutor in Baltimore County, Md., puts it this way: "How do you put a price tag on crimes that don't happen because the threat of the death penalty deters them?"