Although the nullification crisis was ostensibly about South Carolina’s refusal to collect federal tariffs, many historians believe it was actually rooted in growing Southern fears over the movement in the North for the abolition of slavery. When South Carolina threatened to secede if it were forced to pay the tariffs, U.S. President Andrew Jackson said that “disunion by armed force is treason.” Some three decades later, 11 Southern states claimed that their sovereignty gave them the right to secede from the union. This constitutional question was resolved only by the victory of the North (federal government) in the American Civil War.