EVERYBODY with a pulse knew South Carolina was going to secede from the Union.
Next...
Please see post 44.
And your point is well taken: even if this actually had been written in 1832 - which is, to put it mildly, very hard to swallow given the circumstances of its first publication - South Carolina had already threatened to secede and mobilize during the nullification crisis of 1828.
Actually, it was 39 years after Joseph Smith said it, not 20. I misspoke.