William Lowndes Yancey (August 10, 1814July 27, 1863) was a journalist, politician, orator, diplomat and an American leader of the Southern secession movement. A member of the group known as the Fire-Eaters, Yancey was one of the most-effective agitators for secession and rhetorical defenders of slavery. An early critic of John C. Calhoun at the time of the Nullification Crisis of 1832-33, Yancey began to identify with Calhoun and the struggle against the forces of the anti-slavery movement by the late 1830s. In 1849, Yancey was a firm supporter of Calhoun's "Southern Address" and an adamant opponent of the Compromise of 1850.