In the 8 years since the U.S. Supreme Court announced Miller v. Alabama, legislatures and high courts at the state-level have increasingly weighed in on how the reasoning underlying Miller applies anytime a child is sentenced in adult criminal court. This article reviews these recent trends in light of the Court’s emerging proportionality analysis under the 8th Amendment to show why all mandatory or presumptive sentencing schemes that fail to account for child status are unconstitutional. The analysis concludes that this rule should apply retroactively under either of the Teague exceptions for cases on collateral review.