Josh:
...unlike this year South Carolina was only lightly or moderately contested by the frontrunning candidates. And certainly in 1984 and to a large degree in 1988, the nomination contest was already decided, which contributed significantly to Jackson's wins. What's more, caucuses are much easier to win with legwork and organization than primaries if your competitors are not making a big effort in the state.
I find it difficult to believe that President Clinton wasn't aware of this background. All due respect to Jesse Jackson, but he won because the then-caucus was an afterthought in those years.