§ 3214.
A former President and the surviving spouse of a former President may send nonpolitical mail within the United States and its territories and possessions as franked mail. Such mail of a former President and of the surviving spouse of a former President marked “Postage and Fees Paid” in the manner prescribed by the Postal Service shall be accepted by the Postal Service for transmission in the international mails.
([Pub. L. 91–375], Aug. 12, 1970, [84 Stat. 754]; [Pub. L. 93–191, § 4(a)], Dec. 18, 1973, [87 Stat. 742]; [Pub. L. 103–123, title IV, § 6(b)], Oct. 28, 1993, [107 Stat. 1246]; [Pub. L. 105–61, title IV, § 409(b)], Oct. 10, 1997, [111 Stat. 1299].)