Executive order signed by President Obama on March 16, 2012 titled "National Defense Resources Preparedness" makes clear that in the event of a nationally deemed emergency all of resources will fall under the authority of the United States government.
The signing of the National Defense Resources Preparedness executive order grants the Department of Homeland Security, the Department of Agriculture, the Department of Labor, the Department of Defense and other agencies complete control of all US resources, including the ability to seize, confiscate or re-delegate resources, materials, services, and facilities as deemed necessary or appropriate to promote the national defense as delegated by the following agencies:
Sec. 201. Priorities and Allocations Authorities. (a)
(1) the Secretary of Agriculture with respect to food resources, food resource facilities, livestock resources, veterinary resources, plant health resources, and the domestic distribution of farm equipment and commercial fertilizer;
(2) the Secretary of Energy with respect to all forms of energy;
(3) the Secretary of Health and Human Services with respect to health resources;
(4) the Secretary of Transportation with respect to all forms of civil transportation;
(5) the Secretary of Defense with respect to water resources; and
(6) the Secretary of Commerce with respect to all other materials, services, and facilities, including construction materials.