The persistence of the death penalty is only one way in which the United States stands out from the rest of the Western world on crime and punishment.
It also has the highest incarceration rate of any country, with more than two million people behind bars. (China, second in the rankings, has an estimated 1.5 million, and Russia just short of 900,000.) The US has just 5 per cent of the world's population, but 25 per cent of its overall prison population.
Some of the reasons behind the extraordinary machinery of incarceration - including the death penalty - is cultural and historical. In the South, in particular, the phenomenon is inextricably linked to the long history of racial inequality, with blacks put away in numbers vastly disproportionate to their overall population.
The states with the highest ratio of prisoners per population are all former slave states with long traditions of jailhouse brutality, chain gangs and other barbaric practices: Louisiana (816 prisoners per 100,000 people), Texas (694) and Mississippi (669). In many states, blacks are up to 15 times as likely as whites to find themselves behind bars. In Florida, one in three adult black men has a criminal record.
Some trends, though, are more recent - tied, in particular, to the mania for tough-on-crime legislation that has swept state after state in the past 25 years.
The national prison population has quadrupled since 1980, the increase fuelled in particular by the "war on drugs" and the consequent incarceration of hundreds of thousands of petty drug offenders. That, in turn, has exacerbated a host of problems from overcrowding to prison rape to the formation of ultra-violent prison gangs, many of them based on deep racial hatred.
In many cases, prison has taken the place of social services such as drug rehabilitation and mental health counselling and, according to critics of the system, has, in effect, criminalised large portions of the population who would have been much better and much more cheaply treated elsewhere.
Prison guard unions have become major political players, especially in California, home to the single largest prison system in the world, where they bankroll the campaigns of senior state officials and lawmakers. A whole industry has sprung up to support the burgeoning prison population. One writer, Eric Schlosser, memorably described the entire system a few years ago as a "prison-industrial complex".
At a time of tight state budgets, prisons are one area where lawmakers do not hold back from spending lavishly. From next year, California will be spending more on prisons than on its entire higher education system, including close to $1m on a new death row unit at San Quentin outside San Francisco - despite the statewide moratorium on executions. The United States as a whole spends an estimated $60bn a year on its prisons.
by Andrew Gumbel