A year ago this week, the Supreme Court ruled in Miller v. Alabama that it is unconstitutional to impose on a child a mandatory sentence of life without parole. The court stopped short of striking down all life-without-parole sentences for children but required that judges consider a child’s maturity, home environment, role in the crime, potential for rehabilitation and other key factors before ordering this harsh penalty.

Miller was the third Supreme Court ruling in three years to reaffirm the notion that children who run afoul of the law cannot be treated the same way as adults without consideration of their status as children because science tells us — as all parents know — they are fundamentally different.

Still, an investigation by the Center for Law and Global Justice found that the United States remains the only nation in the world known to sentence children to life without parole — a sentence to die in prison.

While young people can commit serious crimes, the children most likely to receive this sentence are among society’s most vulnerable. Nearly 80 percent of youths sentenced to life without parole reported witnessing violence in their homes, according to the Sentencing Project; more than half witnessed weekly violence in their neighborhoods. Most never received treatment for the trauma they experienced at young ages.

A 2005 Human Rights Watch report found that African American youths are sentenced to life without parole at a per capita rate that is 10 times that of white youths convicted of the same crimes, and that more than half of youths who received this sentence had no prior record and, in many cases, had grossly inadequate legal representation. The vast majority of those sentenced to life without parole for crimes committed as youths live in states where the sentence was mandatory.

Miller struck down the statutes in at least 29 states, many of which have considered changes to comply with the ruling. Some states have focused on approaches that would impose the next-harshest available sentence. A few states — including Connecticut, Delaware, Illinois, Washington and Wyoming — have pursued compliance more broadly, seeking reforms that provide periodic reviews of sentences for youths convicted of serious crimes. This approach reflects the notion that children should be held accountable in ways that ensure they will have a second chance at life, increasing the likelihood that they will be motivated to change and be productive members of society when they return home.

The federal government, however, has been silent about addressing this issue.

This month a coalition of more than 65 organizations, including the National PTA, the American Correctional Association and the National Association of Social Workers, called on Attorney General Eric Holder to comply with the core tenets of Miller by reforming the Justice Department policy that allows children to be tried and sentenced as adults in federal court, where life sentences may be imposed. Six months earlier, Holder’s own Task Force on Children Exposed to Violence advised against transferring children to be tried in the adult criminal justice system.

The Obama administration should set an example for states and take this practical but significant step to demonstrate that youths — even those convicted of serious crimes — should be held accountable in ways that reflect their status as children and their capacity to change.