The Pentagon is preparing U.S. military bases to keep operating for at least 90 days without outside support, as it plans for a possible major war that could cripple power grids, disrupt supply chains and threaten critical infrastructure on American soil. The requirement is part of FORTRESS, a broader military initiative aimed at ensuring American forces can keep fighting even if the civilian systems they depend on are disrupted, according to documents reviewed by Fox News Digital.
Pentagon chief spokesperson Sean Parnell told Fox News Digital that the department does not want to depend on standard civilian municipal infrastructure to run national defense. "We just simply can't," he said. "It's an intolerable risk." He added that "power is combat now," arguing that without electricity, the military would lose communications, water, logistics, assembly lines and basic command structures.
Under FORTRESS, every major military installation in the continental United States would be expected to sustain essential operations independently for at least 90 days. That includes access to electricity, water, fuel and communications. The standard goes beyond a plan announced earlier by the Pentagon to reduce major installations' dependence on civilian power grids, extending the requirement to the other essential services needed to sustain military operations.
A central concern is the military's reliance on civilian power grids, which support everything from communications and logistics to weapons manufacturing. FORTRESS envisions portable nuclear reactors, large-scale battery storage and microgrids capable of disconnecting military installations from the civilian electrical grid, allowing them to keep operating during prolonged power disruptions. Parnell said that "mission-critical power must be independent, hardened, and redundant."
The strategy also anticipates major disruptions to the global supply chains that provide the military with weapons, equipment and critical materials. Parnell said that the next conflict would likely be fought on multiple fronts and that global supply chains would break when that happens. To prepare, FORTRESS calls for strategic reserves of munitions, fuel, critical minerals, electronics, spare parts and medical supplies that could sustain operations if international supply routes are cut or domestic manufacturers cannot keep pace with wartime demand. Reserve targets would depend on how quickly supplies are consumed in a major conflict and how long manufacturers would need to replace them.
For the military's most critical defense dependencies, the initiative requires at least two qualified supply or production pathways. The aim is to reduce the risk that losing a single factory, supplier or industrial capability could interrupt operations.
Another component involves preparing the civilian manufacturing sector to support wartime mobilization. Through the Civil Reserve Manufacturing Network, an existing initiative incorporated into FORTRESS, the Pentagon plans to identify commercial factories able to shift to defense production during a crisis. Planning includes assessing manufacturers' capabilities and setting technical specifications, cybersecurity protections, contracting arrangements and conversion procedures in advance, rather than waiting for a conflict to begin. FORTRESS also calls for recurring industrial stress tests and mobilization exercises to test whether manufacturers could keep producing through prolonged disruptions.
Beyond energy and manufacturing, the initiative includes efforts to strengthen military communications, navigation and satellite capabilities against interference. These preparations would help maintain operations if GPS signals are jammed or space-based assets are disrupted. Taken together, the measures are intended to reduce the military's dependence on civilian infrastructure and vulnerable supply networks during a prolonged conflict.
Parnell framed the plan as a response to changed strategic assumptions. "I realized that a lot of the way we think about homeland defense was built around the antiquated assumption that two oceans would protect us," he said. He credited President Trump with paving the way for new thinking, citing Golden Dome, a renewed focus on the Western Hemisphere, Greenland and Panama. Parnell summed up the rationale this way: "You don't want to be making these decisions in the middle of a global multi-front conflict. We have to have a plan." He described FORTRESS as an insurance policy for the homeland, designed to ensure American forces can keep operating even if a major war disrupts the infrastructure and supply chains they rely on.