Joint Electromagnetic Spectrum Operations Readiness Act of 2018 This bill requires the Department of Defense (DOD) to develop and implement a capability to conduct joint campaign modeling for joint electromagnetic spectrum operations. The term "joint electromagnetic spectrum operations" means those activities consisting of electronic warfare and joint electromagnetic spectrum management operations used to exploit, attack, protect, and manage the electromagnetic operational environment to achieve a military commander's objectives. DOD shall: (1) conduct an assessment of required joint electromagnetic spectrum operations capabilities and capacity based on a review of all level 3 and level 4 contingency plans, and (2) submit to the congressional defense committees reports on its readiness with respect to joint electromagnetic spectrum operations.