10 U.S.C. § 124

(a) Lead Agency .— (1) The Department of Defense shall serve as the single lead agency of the Federal Government for the detection and monitoring of aerial and maritime transit of illegal drugs into the United States. (2) The responsibility conferred by paragraph (1) shall be carried out in support of the counter-drug activities of Federal, State, local, and foreign law enforcement agencies. (b) Performance of Detection and Monitoring Function .— (1) To carry out subsection (a), Department of Defense personnel may operate equipment of the Department to intercept a vessel or an aircraft detected outside the land area of the United States for the purposes of— (A) identifying and communicating with that vessel or aircraft; and (B) directing that vessel or aircraft to go to a location designated by appropriate civilian officials. (2) In cases in which a vessel or an aircraft is detected outside the land area of the United States, Department of Defense personnel may begin or continue pursuit of that vessel or aircraft over the land area of the United States. (c) United States Defined .— In this section, the term “United States” means the land area of the several States and any territory, commonwealth, or possession of the United States.