Which politician proposed the idea of nullification?

The idea of nullification was primarily proposed by Thomas Jefferson and James Madison in the late 18th century. They articulated this concept in the Kentucky and Virginia Resolutions of 1798, arguing that states had the right to nullify Federal Laws they deemed unconstitutional. This idea was later championed by other politicians, notably John C. Calhoun, in the context of states' rights and tensions over federal authority.