10 U.S.C. § 1099

(a) Establishment of System .— The Secretary of Defense, after consultation with the other administering Secretaries, shall establish a system of health care enrollment for covered beneficiaries who reside in the United States. (b) Description of System .— Such system shall— (1) allow covered beneficiaries to elect to enroll in a health care plan, or modify a previous election, from eligible health care plans designated by the Secretary of Defense during— (A) an annual open enrollment period; and (B) any period based on a qualifying event experienced by the beneficiary, as determined appropriate by the Secretary; or (2) if necessary in order to ensure full use of facilities of the uniformed services in a geographical area, assign covered beneficiaries who reside in such area to such facilities. (c) Health Care Plans Available Under System .— A health care plan designated by the Secretary of Defense under the system described in subsection (a) shall provide all health care to which a covered beneficiary is entitled under this chapter. Such a plan may consist of any of the following: (1) Use of facilities of the uniformed services. (2) A plan under the TRICARE program. (3) Any other health care plan contracted for by the Secretary of Defense. (4) Any combination of the plans described in paragraphs (1), (2), and (3). (d) Payment Options .— (1) A member or former member of the uniformed services, or a dependent thereof, eligible for medical care and dental care under section 1074(b) or 1076 of this title shall pay a premium for coverage under this chapter. (2) To the maximum extent practicable, a premium owed by a member, former member, or dependent under paragraph (1) shall be withheld from the retired, retainer, or equivalent pay of the member, former member, or dependent. In all other cases, a premium shall be paid in a frequency and method determined by the Secretary. (e) Regulations .— The Secretary of Defense, after consultation with the other administering Secretaries, shall prescribe regulations to carry out this section.