10 U.S.C. § 10143: Ready Reserve: Selected Reserve

(a) Within the Ready Reserve of each of the reserve components there is a Selected Reserve. The Selected Reserve consists of units, and, as designated by the Secretary concerned, of Reserves, trained as prescribed in section 10147(a)(1) of this title or section 502(a) of title 32, as appropriate. (b) The organization and unit structure of the Selected Reserve shall be approved—(1) in the case of all reserve components other than the Coast Guard Reserve, by the Secretary of Defense based upon recommendations from the military departments as approved by the Chairman of the Joint Chiefs of Staff in accordance with contingency and war plans; and (2) in the case of the Coast Guard Reserve, by the Secretary of Homeland Security upon the recommendation of the Commandant of the Coast Guard.