The article is incorrect. The original seven Southern states seceded before the tariff was voted on.
John C. Calhoun developed his concept of nullification in response to Yankee-inspired protective tariffs over 3 decades before the Civil War, proving that tariffs were a long-running bitter issue between North & South. The only difference between the Confederate constitution and the U.S. one was that the Confederate one banned protective tariffs. Try reading some real history for a change, instead of Unionist propaganda.