The United States is the only country in the world that sentences juveniles -- individuals younger than 18 years old -- to life in prison without parole. On Tuesday, the American Civil Liberties Union and Columbia Law School's Human Rights Institute argued in front of the Inter-American Commission on Human Rights that children convicted of serious crimes don't deserve such a severe sentence.

"You need to have sentences that are intended to rehabilitate a child," Deborah LaBelle, an attorney with the ACLU, told The Huffington Post. "You need to incarcerate them for the least amount of time to achieve that goal."

Among the cases being highlighted by the groups is that of Juwan Wickware, who was 16 when he participated in a robbery that resulted in the death of a Flint, Mich., pizza delivery man.

Prosecutors said that on April 7, 2010, Wickware and another teen, Donqua Williams, shot at Michael Nettles -- Williams with a .40-caliber pistol and Wickware with a .22-caliber rifle, according to Michigan Live.

A .40-caliber bullet was found in Nettles and .22-caliber bullet casings were found at the scene. "It is absolutely clear Juwan didn't shoot him," said LaBelle.

LaBelle explained to HuffPost that to be convicted of felony murder in Michigan, one need not be directly responsible for killing someone, but merely complicit in a felony crime that results in another person's death.

"If you're in concert, or you're engaged in a plan, and a murder results, they find that you're involved in a felony murder," LaBelle said. "Even if you're not the person who committed the homicide, you get the same sentence."

Wickware, who had no previous convictions, was found guilty of felony murder.

In 2012, shortly before Wickware was sentenced, the U.S. Supreme Court ruled that mandatory sentences of life without parole for juvenile offenders constituted cruel and unusual punishment. But the court did find that judges could use discretion in imposing the sentence.

In August 2012, when Genesee Circuit Judge Archie Hayman sentenced Wickware to life without parole (as heard in the video above), Hayman said he was "convinced that it is the right thing to do in this particular situation."

A jury found Williams, Wickware's accomplice, to be not guilty, after a woman who was in the deliveryman's Jeep on the night of the slaying said she thought a third man killed Nettles.

Today in the U.S., more than 2,600 people are currently serving sentences of life without parole because of crimes they committed as children, LaBelle said.

The ACLU believes the sentence should be banned outright for juvenile offenders, and Labelle cited the United Nations Commission Against Torture's determination that the sentence was tantamount to torture in such circumstances. The Convention for the Elimination of Racial Discrimination also found that the application of the sentence is tinged with racial inequities.

But proponents of the practice contend that sometimes the punishment isn't about rehabilitation.

"The one thing that we don't know is what the potential of the life would be that was snuffed out in the crime," Arkansas Attorney General Dustin McDaniel told NPR in 2012. "The hypothetical of who might be rehabilitated in prison is a hard one to analyze, but there have to be some circumstances under which these persons can serve life without parole."

Former Alabama Solicitor General John Neiman agreed.

"As a moral matter, it is okay for a government to say, 'Even if there is a possibility that someone will rehabilitate themselves, if a person commits a sufficiently egregious crime, then they just deserve a very severe sentence,'" Neiman told NPR.

But to LaBelle, the issue is not just about ending an overly cruel, unproductive and misguided sentence -- she said the practice also hurts America's international reputation.