U.S. v. Richmond
In U.S. v. Richmond, 550 F.Supp. 605 (1982), the defendant, "a Member of Congress, agreed to plead guilty to income tax evasion (26 U.S.C. 7201), supplementing the salary of a federal employee (18 U.S.C. 209) and possession of marijuana (21 U.S.C. 844)." Id. at 606.
"He also undertook to immediately resign from Congress and withdraw as a candidate for re-election" and, in turn, the government "consented not to prosecute him for a variety of other crimes." Id.
The United States District Court for the Eastern District of New York held that "those portions of the plea agreement pertaining to resignation from Congress and withdrawal as a candidate for re-election are void" because "they represent an unconstitutional interference by the executive with the legislative branch of government and with the rights of the defendant's constituents." Id.