U.S. Department of State Foreign Affairs Manual Volume 7 - Consular Affairs
7 FAM 1113 NOT INCLUDED IN THE
MEANING OF “IN THE UNITED STATES”
(CT:CON-314; 08-21-2009)
c. Birth on a U.S. Military Base Outside of the United States of Bireth on U.S. Embassy or Consulate Premises Abroad:
(1) Despite widespread popular belief, U.S. military installations abroad and U.S. diplomatic or consular facilities abroad are not part of the United States within the meaning of the 14th Amendment. A child born on the premises of such a facility is not born in the United States and does not acquire U.S. citizenship by reason of birth.
http://www.state.gov/documents/organization/86755.pdf
Law of Nations. See reply 658.