This brief explores the justification of the death penalty, using the 2018 Marjorie Stoneman Douglas High School shooting in Parkland, Florida, as a case study. The authors argue that when an offender's impairments severely impact their ability to make rational decisions, the death penalty is unjustified, regardless of the crime's severity. The book examines the case of Nikolas Cruz, the school shooter diagnosed with fetal alcohol spectrum disorder (FASD), including:  The nature of FASD, how it was measured, and how it manifested in Cruz. The impact of FASD on Cruz's adaptive functioning. The concept of "psychiatric overshadowing" and how it led to the oversight of Cruz's FASD and associated brain damage by many mental health experts. The broader implications of FASD, with a recommendation to expand death penalty exemptions to include disorders equivalent to intellectual disabilities (ID). By focusing on the highly controversial Cruz case, the authors-key experts from the trial-offer insights into FASD and its often-overlooked role in determining criminal responsibility and sentencing. This book is essential for forensic psychologists, psychiatrists, mental health professionals, FASD/DD specialists, researchers, and legal professionals involved in death penalty defense work.