Children are not small adults. That is why we have, among other age-specific accommodations, an education system to nurture young minds and children’s hospitals to treat growing bodies. Our justice system also recognizes the distinction, with separate procedures and facilities for processing juvenile cases and detaining youth offenders.

Still, relics of a less enlightened past remain. The time has come to address one such relic in our justice system: the use of solitary confinement for young people.

It has long been a central tenet of the juvenile justice system that young people should not be punished purely for punishment’s sake, but rather with the goal of rehabilitation in mind. Congress reaffirmed this goal in 2002 when it reauthorized the major federal juvenile justice law, the Juvenile Justice Delinquency Prevention Act, stating the imperative that delinquency prevention programs be designed to help young people in the system “become responsible and productive members of their communities.”

Put simply, juvenile solitary confinement is divorced from – even contrary to – this goal. It should be eliminated.

That’s why I joined a bipartisan group of senators in reintroducing legislation developed by Sen. Cory Booker (D-NJ) called the MERCY Act. This legislation would prohibit the use of solitary confinement for youths in the federal system except in extreme circumstances involving those who pose an immediate risk of physical harm to themselves or others. Even in those cases, the legislation includes several requirements to make sure that confinement is a last resort and tightly limited in duration.

Secluding young people in solitary confinement serves no public safety goal. Research suggests that the use of solitary confinement may actually make prisons less safe. Ohio, for example, decreased seclusion hours by 89 percent between 2014 and 2015 in juvenile facilities and at the same time saw a drop of 22 percent in the amount of violence in those facilities. Research also suggests that, far from rehabilitating detainees and preparing them for release, solitary confinement actually increases recidivism.

Solitary confinement hurts the kids the system is supposed to help. Studies show that solitary confinement stunts brain development in young people and is linked to the onset or worsening of serious mental health problems, including depression, anxiety and severe behavioral conditions. It’s little wonder that, according to a 2009 report by the Department of Justice, more than half of suicides of children in juvenile facilities occurred while they were in isolation. Isolating young people also prevents them from accessing the programs intended to help them develop the skills to live productive and well-adjusted lives upon release.

As a father, my heart breaks imagining any child locked up, alone and scared, in a fluorescently lit room with cold linoleum floors and bare concrete walls. A report in the Philadelphia Inquirer last year about a boy named Donyea Phillips has stayed with me ever since I first read it. At age 16, Donyea found himself in segregated housing at Philadelphia Industrial Correctional Center, an adult facility. He attempted to hang himself with his bedsheet. “It was the worst time of my life,” he said.

Even young people who have done terrible things deserve to be treated humanely and in keeping with the principles of the juvenile justice system. We have made progress, thanks in large part to the excellent work of organizations like the Philadelphia-based Juvenile Law Center and the Youth Sentencing & Reentry Project, as well as campaigns like Stop Solitary for Kids, among others. Pennsylvania banned locking youths in solitary confinement and limits the use of seclusion in an unlocked room. Many other states are making important reforms too. There is more work to do at the state level, but it is past time the federal government caught up and provided a national model for reform.

President Obama issued an executive order last year to limit juvenile solitary confinement in accordance with the principles of the MERCY Act. In announcing his order, President Obama referenced the tragic story of Kalief Browder, a teenager from the Bronx who was incarcerated in 2010 in Rikers Island, also an adult facility, while awaiting trial for stealing a backpack. He ended up spending almost two years in solitary confinement and attempted suicide multiple times. His case was dismissed by the court and he was released in 2013, but he came home a changed person and reportedly exhibited symptoms of post-traumatic stress disorder. He committed suicide in 2015 at the age of 22.

Kalief’s story has gotten national attention, including a six-part documentary, produced by Jay-Z, called "Time: The Kalief Browder Story," that recently shown on Spike TV. Everyone should watch this important series, keeping in mind that Kalief’s story is not unique – there are thousands of kids just like him languishing in solitary confinement at this very moment. For the sake of those kids, it is time to build on President Obama’s order and pass the MERCY Act to permanently codify in federal law critical protections for young people in the justice system.