39 U.S. Code § 413 - Postal services at diplomatic posts
(a) The Postal Service and the Department of State may enter into 1 or more agreements for field testing to ascertain the feasibility of providing postal services through personnel provided by the Department of State at branch post offices established by the Postal Service in United States diplomatic missions at locations abroad for which branch post offices are not established under section 406.
(b) To the extent that the Postal Service and the Department of State conclude it to be feasible and in the public interest, the Postal Service may establish branch post offices at United States diplomatic missions in locations abroad for which branch post offices are not established under section 406, and the Department of State may enter into an agreement with the Postal Service to perform postal services at such branch post offices through personnel designated by the Department of State.
(c) The Department of State shall reimburse the Postal Service for any amounts, determined by the Postal Service, equal to the additional costs incurred by the Postal Service, including transportation costs, incurred by the Postal Service in the performance of its obligations under any agreement entered into under this section.
(d) Each agreement entered into under this section shall include—
(1) provisions under which the Department of State shall make any reimbursements required under subsection (c);
(2) provisions authorizing the Postal Service to terminate the agreement, and the services provided thereunder, in the event that the Department of State does not comply with the provisions under paragraph (1); and
(3) any other provisions which may be necessary, including provisions relating to the closing of a post office under this section if necessary because a post office under section 406 is established in the same location.