Rupert Cornwell: Will the recession be the death of Old Sparky?

Out of America: The average cost of a death penalty case has risen to as much as $250m. For many states, that's simply too much

Every cloud has its silver lining, even the lead-dark ones of the current recession. The economic downturn is putting huge pressure on incomes, jobs and corporate balance sheets – but also on capital punishment, that practice long since abandoned elsewhere in the industrial world, but which the US shares with such beacons of human rights as Iran, China and Saudi Arabia.

Last week, little noticed amid the uproar over those AIG bonuses, New Mexico became the 15th state (the 16th if the District of Columbia is included) and the first in the southern half of the country to abolish the death penalty. The recession, to be fair, had little to do with Governor Bill Richardson's decision to sign the repeal into law. Nor will it make much difference to the statistics of state-sanctioned killing in America.

Since the Supreme Court lifted its ban on executions in 1976, New Mexico has put just one person to death – compared with 435 over the same period by Texas. But it is merely the latest sign of how, slowly but seemingly inexorably, America is turning away from the death penalty.

And, though Richardson is a Democrat, he is no dewy-eyed liberal. Some murders, he still believes, are so heinous that death is a "just punishment". But two factors tipped the scales: the risk of executing the wrong person and the fact that the alternative of life without parole was no less of a punishment. "Those cells may be worse than death," he said.

Right now in the US, the death penalty indicator is pointed firmly downward. Last year, 37 people were executed, compared with 98 in 1999, the busiest year for America's death chambers in the modern era. Increasingly it is no longer southern states in general that use it, but one state – Texas – which alone accounted for half of last year's executions, and 12 of the 20 carried out so far in 2009. Offered a choice of sentence between life without parole and death for someone convicted of first-degree murder, a narrow majority of Americans (48 per cent to 47 per cent) now favour the former, according to a recent poll.

Since the late 1990s, the number of death sentences handed down by US courts has dropped by two-thirds, to 111 in 2008. The national death row population may be fairly static at around 3,300, but the typical resident is growing steadily older, not least because the average delay between sentencing and execution now exceeds 12 years and, in some cases, 20. Indeed, a death row inmate is as likely to die in the prison hospital as in the electric chair.

But to that and the other familiar moral arguments against capital punishment – the randomness of the death penalty, its racial bias, the doubts about whether it is a deterrent, and, above all, the risk of putting to death an innocent person – can be added another. In these straitened times, executing people is just too expensive.

By and large it is far cheaper to keep a person in jail for the rest of his life than to seek to kill him. New Jersey, which had eight death row inmates when it became the first state to abolish the death penalty after the Supreme Court ruling, had not actually executed anyone since 1963. As one official dryly noted: "Over the last quarter century, we've spent a quarter of a billion dollars on a capital punishment system that executed no one."

Everywhere the story is similar. In Maryland, which this year came close to getting rid of the death penalty, the average capital case ending with a death sentence costs $3m (£2.1m), almost three times as much as one where prosecutors do not seek the death penalty.

In Colorado, which has put just one person to death since 1976, the state legislature is taking up a bill that would scrap the death penalty and use the savings to fund a cold-case unit to tackle the 1,400 unsolved murders on police books. Kansas and Montana may follow New Mexico's example, while other states, such as Louisiana, are keeping the death penalty option, but cutting back on the number of capital cases. As the state's Attorney General, Buddy Caldwell, puts it, such cases are "like playing on a $100-a-roll table instead of a nickel or dime table".

Capital punishment is not going to disappear in a hurry – Texas alone will make sure of that. But, there as elsewhere, the question is the same: should money be spent on the death penalty when states are cutting jobs and services? Even in California, with the most dysfunctional capital punishment system of all, voices are to be heard against it.

Since 1976, America's most populous state has executed just 13 people – which, according to the Los Angeles Times, works out at some $250m per head. Not only is a capital trial, which typically lasts three times as long as a non-capital one, far more expensive. A death sentence triggers a lengthy and costly appeals process. All the while, the state is paying $90,000 per prisoner per year to keep an inmate in an individual cell with extra guards.

Nonetheless, California still plans to spend $400m to replace the overcrowded and crumbling death row at San Quentin prison. For now, and despite having to grapple with a budget deficit of $40bn, it is sticking with the machinery of death. One day, however, even Californians may conclude that, at $250m a time, executions are a pretty bad deal.