The ACLU says the law violates the U.S. Constitution because it is "cruel and unusual punishment."
In a press release, the ACLU says the lawsuit is:
...on behalf of nine Michigan citizens who were sentenced to life in prison without the possibility of parole for crimes committed when they were minors. The lawsuit charges that a Michigan sentencing scheme that denies the now-adult plaintiffs an opportunity for parole and a fair hearing to demonstrate their growth, maturity and rehabilitation constitutes cruel and unusual punishment and violates their constitutional rights.
According to the release:
The U.S. is the only country in the world that sentences youth to life without parole, and Michigan incarcerates the second highest number of people serving life sentences without parole for crimes committed when they were 17 years old or younger. Currently, there are 350 individuals serving such mandatory life sentences in Michigan. This includes more than 100 individuals who were sentenced to life without parole who were present or committed a felony when a homicide was committed by someone else.