The Treaty Clause of the federal Constitution declares that the President shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur. The consensus of doctrine, history, and scholarship, exemplified by the holding in Missouri v. Holland, 252 U.S. 416 (1920), is that the Treaty Clause affirmatively grants to the President and Senate a free-standing, quasi-legislative power that contains no internal constitutional limitations. Thomas Jefferson notably disagreed. Jefferson viewed the treaty power as a purely implementational power that could only be used to effectuate other federal powers. From the standpoint of original meaning, Jefferson was right. In this articl...