14 U.S.C. § 3902: Purpose of the Coast Guard Auxiliary

(a) In General.—The purpose of the Auxiliary is to assist the Coast Guard as authorized by the Commandant, in performing any Coast Guard function, power, duty, role, mission, or operation authorized by law. (b) Limitation.—The Auxiliary may conduct a patrol of a waterway, or a portion thereof, only if—(1) the Commandant has determined such waterway, or portion thereof, is navigable for purposes of the jurisdiction of the Coast Guard; or (2) a State or other proper authority has requested such patrol pursuant to section 701 of this title or section 13109 of title 46.