Newly emerging US cyberspace warfighting concepts highlight the need to update US legal doctrine. Concepts adapted to future high-intensity, high-paced armed conflict, including command post dispersal and integration of cyberspace into other targeting domains, present opportunities to refine US understandings of the law of war attack threshold and overlooked rules applicable to destruction and seizure. The advantages of staking out clear and current opinio juris on these and other matters extend beyond providing responsible and consistent operational law advice. Updated and authoritative military cyber legal doctrine will serve the strategic and diplomatic legal interests of the United States and the international legal system as a whole.