There seems to be a common wisdom that in 1860, pro-slavery and secessionist Southerners supported John Breckenridge and pro-union Southerners supported John Bell or Stephen Douglas. One only needs to look at the ‘Who would you vote for’ thread to see the unmitigated shock some people had at people voting for Breckenridge, yet no such concern over Douglas/Bell. However, if you look at the result at the county level, you can see a different trend to explain the vote.
These maps are from
http://geoelections.free.fr/USA/elec_comtes/There is a positive correlation in a few states between Breckenridge support and the density of the slave population. North Carolina’s heavily slave populated east voted strongly for Breckenridge and the west had a strong Bell vote. The Savannah area was also strong for Breckenridge, and Eastern Tennessee was strong for Bell. However there are some very strong contradictions in the data as well. If this theory is true, the heavily slave areas along the Mississippi river should have been heavily pro-Breckenridge, but in fact it was among his weakest area in those states.
Bell’s vote in Missouri was strongest in the more heavily slave area, with Douglas and Breckenridge splitting everywhere else. Northern Alabama, historically the more anti-secessionist part of the state also went mostly for Breckenridge.
In fact, the explanation for breakdown of Southern votes is the partisanship between Democrats and former Whigs, which broke down uniquely in every state. Bell captured the votes of Southerners who traditionally voted Whig and Breckenridge (and sometimes Douglas) gained the votes of reflexive Democrat voters. If you voted for Polk in 1844, chances are you voted for Breckenridge in 1860. Compare the 1860 map to 1852 and 1844. Only in Virginia and Maryland was there a significant pro-Bell outlier, and I suspect this is because the threat of civil war would obviously have more concern in these two states. Also the former Whig vote in the Deep South was much weaker than in the previous elections, mostly because the Whig Party mostly disappeared in the Deep South following the internal fights over slavery. It's also important to note that in 1844 that the Whig Party was strongest in the more slave populated areas in the Deep South.
