2 U.S.C. § 1432: Political affiliation and place of residence

(a) In generalIt shall not be a violation of any provision of section 1311 of this title to consider the—(1) party affiliation; (2) domicile; or (3) political compatibility with the employing office; of an employee referred to in subsection (b) with respect to employment decisions. (b) “Employee” definedFor purposes of subsection (a), the term “employee” means—(1) an employee on the staff of the leadership of the House of Representatives or the leadership of the Senate; (2) an employee on the staff of a committee or subcommittee of—(A) the House of Representatives; (B) the Senate; or (C) a joint committee of the Congress; (3) an employee on the staff of a Member of the House of Representatives or on the staff of a Senator; (4) an officer of the House of Representatives or the Senate or a congressional employee who is elected by the House of Representatives or Senate or is appointed by a Member of the House of Representatives or by a Senator (in addition an employee described in paragraph (1), (2), or (3)); or (5) an applicant for a position that is to be occupied by an individual described in any of paragraphs (1) through (4).