The 2nd time they did. During the Nullification Crisis of 1830 it wasn’t the issue. The Nullification crisis was an attempt by South Carolina to refuse the laws of the National Government due to excessive tariffs by threatening secession. Tariffs were the continuing, burning, simmering, underlying issue. The slavery issue, to the South, was the ‘straw that broke the camel’s back’ by 1860.
You cannot separate the tariff issue from the slavery issue, they are connected
Except the tariffs were low when South Carolina pretended to secession.
We have nice parting gifts though.