Roughly 2,300 people are behind bars for life with no chance of winning their freedom for crimes they committed before their 18th birthday. Seventy-nine of them are in prison for crimes that took place when they were 14 or younger.
The precise contours of an eventual ruling were not apparent after arguments Tuesday, but several justices said they were troubled by the way some states try and sentence young people accused of crimes.
Justice Anthony Kennedy raised the lack of flexibility in sentencing young killers. Several states that try people younger than 18 in adult courts allow for only one sentence, life with no chance of parole, for defendants who are convicted of murder.