Over the course of the last half-century, intensive care units have been the setting for many ethical and legal debates in medicine. This article outlines 3 important domains that lie at the intersection of critical care, palliative care, ethics, and the law: withholding and withdrawal of potentially life-sustaining therapies, making decisions for critically ill patients who lack decision-making capacity, and approaching cases of perceived futility when patients and families still request everything that is medically possible. Important principles and precedents that underlie our understanding of how nurses should approach critically ill patients are reviewed.