Article III: Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort.
Fourteenth Amendment, Section 3: No person ... shall ... hold any [state or federal] office, ... who, having previously taken an oath, as [a state or federal officer]i ... to support the Constitution of the United States, shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof.