To decide whether to secede from the United States
Explanation:
The leaders of the South Carolina Ordinance of Secession of 1860 convention meet "to decide whether to secede from the United States."
This is evident in the fact that few days after the election of Abraham Lincoln, the South Carolina legislature called a convention that took place in Charleston, and eventually, on December 20, 1860, the convention agreed without opposition to secede from the United States.
