In the case of Evan Miller v. Alabama, 2011, the U.S. Supreme Court ruled that mandatory life sentences without parole for juvenile offenders are unconstitutional. The decision was based on the Eighth Amendment's prohibition against cruel and unusual punishment. The court held that children should be treated differently from adults due to their lack of maturity and underdeveloped sense of responsibility which can lead to reckless behavior; they also have a greater capacity for change than adults do, thus rehabilitation is a more appropriate goal than retribution in sentencing juveniles convicted of serious crimes like murder. This ruling built upon previous decisions limiting severe punishments for juvenile offenders such as Roper v Simmons (2005) where death penalty was declared unconstitutional for juveniles and Graham v Florida (2010) where life imprisonment without possibility of parole was deemed inappropriate for non-homicide offenses committed by minors.

In the dissenting opinion for Evan Miller v. Alabama, Chief Justice Roberts, joined by Justices Scalia, Thomas and Alito argued that the court's decision to categorically ban life without parole sentences for juveniles convicted of homicide was an overreach. They contended that this ruling disregarded the principle of judicial discretion in sentencing and failed to consider individual circumstances surrounding each case. The dissenters believed it should be left up to trial judges or juries who are familiar with specific details of a crime and can evaluate factors such as age, maturity level, family environment etc., before deciding on appropriate punishment. They also pointed out that many states had already outlawed juvenile life without parole sentences indicating democratic processes were addressing concerns about harsh punishments for young offenders effectively.