The rapid expansion of cyberspace presents unprecedented challenges for operational commanders going forward. Responding to the increasing role and importance of this domain, U.S. Cyber Command (CYBERCOM) recently began establishing Cyber Support Elements (CSE) at the combatant commands. Given this, the question arises as to how CYBERCOM and its supported operational commanders should prioritize cyberspace operations to best support full spectrum operations. This paper argues that operational commanders should focus predominantly on cyber defense for three reasons. First, cyber threats to the military are at an all-time high and increasing at an extraordinary rate, so operational commanders cannot afford to let their guards down. Second, the military's cyber dependence is a critical vulnerability; a strong cyber defense protects essential networks and enables operational commanders to effectively employ their vast arsenal of cyber-dependent weapons and systems. Third, cyber defense is the best deterrent; denying the benefits and reducing the value of attacks is the most effective way to deter adversaries from attacking the U.S. in cyberspace.