Many lifers aren't in prison for murder, but for lesser crimes:

Some critics of life sentences say they are overused, pointing to people like Jerald Sanders, who is serving a life sentence in Alabama. He was a small-time burglar and had never been convicted of a violent crime. Under the state's habitual offender law, he was sent away after stealing a $60 bicycle.

Fewer than two-thirds of the 70,000 people sentenced to life from 1988 to 2001 are in for murder, the Times analysis found. Other lifers - more than 25,000 of them - were convicted of crimes like rape, kidnapping, armed robbery, assault, extortion, burglary and arson. People convicted of drug trafficking account for 16 percent of all lifers.

Violent crime is committed mostly by young people, whose violence declines as they age in jail. When they get really old, the taxpayer is stuck with the costs of paying for their medical care and operations. Is their continued incarceration really necessary? Often, the answer is no.

Life sentences certainly keep criminals off the streets. But, as decades pass and prisoners grow more mature and less violent, does the cost of keeping them locked up justify what may be a diminishing benefit in public safety? By a conservative estimate, it costs $3 billion a year to house America's lifers. And as prisoners age, their medical care can become very expensive. At the same time, studies show, most prisoners become markedly less violent as they grow older.

Other countries do it differently. It's time we did too.