Final answer:
Unionists did not support South Carolina's secession; it is a false statement. Unionists in the South generally remained loyal to the Union and some actively opposed and fought against the Confederacy. The statment is false.
Step-by-step explanation:
The assertion that Unionists supported South Carolina's secession is false. Unionists, particularly in the southern states, were those who remained loyal to the Union during the Civil War period. In South Carolina and across other states that joined the Confederacy such as Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas, the debates were not about whether they should secede but about when and how to go about it.
The proponents of secession, who were mostly secessionists and not Unionists, believed they had the legal right to leave the Union and sought to protect their property rights, which were deeply entangled with the institution of slavery. Unionists in southern states often opposed the Confederacy and some even joined the Union army to work against the Confederate cause. Additionally, in areas such as western Virginia and eastern Tennessee, there was significant pro-Union sentiment that resisted secession efforts.