Defense Health Agency. The Defense Health Agency (DHA) is a joint, integrated Combat Support Agency that enables the U.S Army, U.S Navy, and U.S Air Force medical services to provide a medically ready force and ready medical force to Combatant Commands in both peacetime and wartime.
Definition of preemption. 1a : the right of purchasing before others; especially : one given by the government to the actual settler upon a tract of public landb : the purchase of something under this right.
The preemption doctrine refers to the idea that a higher authority of law will displace the law of a lower authority of law when the two authorities come into conflict. Federal Preemption. When state law and federal law conflict, federal law displaces, or preempts, state law, due to the Supremacy Clause of the Constitution. U.S. Const. art. VI., Â§ 2.