Which figure is associated with South Carolina's secession from the Union?

John C. Calhoun is a pivotal figure in the history of South Carolina's secession from the Union due to his strong advocacy for states' rights and his belief in the importance of slavery to the Southern economy. As a prominent politician and a leading voice for Southern interests in the first half of the 19th century, Calhoun argued that states had the right to nullify federal laws they deemed unconstitutional and ultimately that they could secede from the Union if their rights were threatened. His ideological foundations and public speeches laid the groundwork for the secession movement in South Carolina, which was the first state to secede from the Union in December 1860, following his principles.

In contrast, while William Yancey was an influential fire-eater advocating for secession in Alabama, Harriet Beecher Stowe is primarily known for her anti-slavery novel "Uncle Tom's Cabin," which aimed to galvanize opposition to slavery rather than support secession. Robert E. Lee, a general in the Confederate Army, became significant after the secession and is more associated with military leadership during the Civil War rather than the political causes behind secession itself.