18 U.S.C. § 879: Threats against former Presidents and certain other persons

(a) Whoever knowingly and willfully threatens to kill, kidnap, or inflict bodily harm upon—(1) a former President or a member of the immediate family of a former President; (2) a member of the immediate family of the President, the President-elect, the Vice President, or the Vice President-elect; (3) a major candidate for the office of President or Vice President, or a member of the immediate family of such candidate; or (4) a person protected by the Secret Service under section 3056(a)(6); shall be fined under this title or imprisoned not more than 5 years, or both. (b) As used in this section—(1) the term “immediate family” means—(A) with respect to subsection (a)(1) of this section, the spouse of a former President during a former President’s lifetime, the surviving spouse of a former President until the surviving spouse’s death or remarriage, and minor children of a former President until they reach sixteen years of age; and (B) with respect to subsection (a)(2) and (a)(3) of this section, a person to whom the President, President-elect, Vice President, Vice President-elect, or major candidate for the office of President or Vice President—(i) is related by blood, marriage, or adoption; or (ii) stands in loco parentis; (2) the term “major candidate for the office of President or Vice President” means a candidate referred to in subsection (a)(7) of section 3056 of this title; and (3) the terms “President-elect” and “Vice President-elect” have the meanings given those terms in section 871(b) of this title.