The Virginia and Kentucky Resolutions of 1798 that James Madison and Thomas Jefferson authored as a repudiation of the Federalist-backed Alien and Sedition Acts of 1798 are incorrectly viewed as originating the idea that John C. Calhoun would develop into his theory of nullification, that is, the right of an individual state to veto federal law. Although these interposition resolutions lacked support from other states, their interstate circulation mobilized a grassroots movement that helped elect Jefferson as President in 1800 and overturned Federalist policies. Despite their political success, what Jefferson and Madison meant by language they used in the resolutions burdened the future efforts of states seeking to monitor the governmental balancing of powers and resulted in a deeply troubling political legacy. Madison drew subtle but crucial constitutional distinctions, yet failed to explain what he meant by the theoretical right of the sovereign people to interpose in the last resort (expressed in the Virginia Resolution and in his Report of 1800). Moreover, Jefferson’s statements that unconstitutional laws were null and void seemingly foreshadowed the remedy of nullification.