For the purpose of this subchapter—

(1) “United States”, when used in a geographical sense means the several States and the District of Columbia; and

(2) “employee” means—

(A) an employee as defined by section 2105 of this title; and

(B) an individual first employed by the government of the District of Columbia before October 1, 1987;

but does not include—

(i) a teacher or librarian of the public schools of the District of Columbia;

(ii) a part-time employee who does not have an established regular tour of duty during the administrative workweek;

(iii) a temporary employee engaged in construction work at an hourly rate;

(iv) an employee of the Panama Canal Commission when employed on the Isthmus of Panama;

(v) an employee of the Veterans Health Administration who is covered by a leave system established under section 7421 of title 38;

(vi) an employee of either House of Congress or of the two Houses;

(vii) an employee of a corporation supervised by the Farm Credit Administration if private interests elect or appoint a member of the board of directors;

(viii) an alien employee who occupies a position outside the United States, except as provided by section 6310 of this title;

(ix) a “teacher” or an individual holding a “teaching position” as defined by section 901 of title 20;

(x) an officer in the executive branch or in the government of the District of Columbia who is appointed by the President and whose rate of basic pay exceeds the highest rate payable under section 5332 of this title;

(xi) an officer in the executive branch or in the government of the District of Columbia who is designated by the President, except a postmaster, United States attorney, or United States marshal;

(xii) a chief of mission (as defined in section 102(a)(3) of the Foreign Service Act of 1980); or

(xiii) an officer in the legislative or judicial branch who is appointed by the President.

Notwithstanding clauses (x)-(xii) of paragraph (2), the term “employee” includes any member of the Senior Foreign Service or any Foreign Service officer (other than a member or officer serving as chief of mission or in a position which requires appointment by and with the advice and consent of the Senate) and any member of the Foreign Service commissioned as a diplomatic or consular officer, or both, under section 312 of the Foreign Service Act of 1980.