http://www.independent.org/newsroom/article.asp?id=346
http://www.gilderlehrman.org/history-by-era/jackson-lincoln/timeline-terms/tariff-1828-tariff-abomination
The "Tariff of Abominations", the Tariff of 1825, had caused a crash of cotton prices of more than 50%, causing great economic hardship in the South. The South was not going to accept another high tariff to protect Northern economic interests at their expense.
http://www.gilderlehrman.org/history-by-era/jackson-lincoln/timeline-terms/tariff-1828-tariff-abomination