After more than five weeks of testimony and seven days of deliberations, the Massachusetts murder trial of Lindsay Clancy ended Friday without a verdict. Clancy was charged with three counts of first-degree murder for the January 2023 deaths of her children, Cora, 5, Dawson, 3, and Callan, 8 months. There was no dispute at trial that Clancy killed the children. The central question was instead one of criminal responsibility: Was Clancy legally responsible for her actions, or was she so profoundly mentally ill that Massachusetts law did not permit the jury to hold her criminally accountable? Twelve jurors could not unanimously answer that question. On September 4, Superior Court Judge William Sullivan declared a mistrial. A mistrial is neither an acquittal nor a conviction. In Clancy’s case, the unusual circumstances surrounding the jury’s deadlock raise important questions about jury unanimity, juror independence, and what happens next. When a Jury Cannot Agree Criminal jury verdicts must be unanimous. But disagreement does not automatically produce a mistrial.  When jurors report that they have reached an impasse, judges …