The era of U.S. electromagnetic spectrum dominance has ended, replaced by contested battlespaces where adversaries like Russia and China employ advanced electronic warfare (EW) to deny critical communications and disable up to 90 percent of standard sensor networks. This new reality demands a fundamental paradigm shift in the design of Wireless Sensor Networks (WSNs) and unattended ground sensors (UGS), moving away from systems built for permissive environments toward resilient architectures optimized for spectrum-denied operations. To ensure network persistence under extreme degradation, future military strategy must embrace self-healing mesh networks that utilize edge AI/ML for real-time jamming detection, advanced Counter EW (CEW) techniques like frequency agility, and operational adaptations such as passive acoustic sensors that emit no signals.