18 U.S. Code § 1751 - Presidential and Presidential staff assassination, kidnapping, and assault; penalties
(d)If two or more persons conspire to kill or kidnap any individual designated in subsection (a) of this section and one or more of such persons do any act to effect the object of the conspiracy, each shall be punished (1) by imprisonment for any term of years or for life, or (2) by death or imprisonment for any term of years or for life, if death results to such individual.
https://www.law.cornell.edu/uscode/text/18/1751