The advantage will always be the attacker’s in cyberwar, so the best possible defense will have to suffice in place of a perfect defense. Five areas of focus can reduce vulnerability in what is essentially the irreversible runaway train of technology: education and training, a clear chain of custody for all networks at all facilities, unambiguous processes and procedures along with explicit guidance on correct behavior in cyberspace operations, more energetic development of advanced ways to manage access to networks and their information, and a formal “cyberspace mishap” investigation apparatus. These steps must not be theory alone; their military implementation is a commander’s responsibility. Lacking that support for all five core areas, a culture of cyberspace accountability will remain elusive.