Graphic by Megan Eloise/The Gazelle

Lasting from 1861 to 1865, the U.S. Civil War was one of the bloodiest wars of the 19th century. The estimated 750,000 soldiers killed outnumber those in all other U.S. American wars combined. One estimate of the death toll is that ten percent of all Northern males 20 to 45 years old, and 30 percent of all Southern white males aged 18 to 40 died.

It also is arguably the most important event in U.S. history. The Union victory resulted in the abolition of slavery and facilitated the process of abolition in other Western Hemisphere countries such as Brazil. The war also furthered the process of political centralization that characterizes the U.S. state to this day.

This devastating conflict was initiated by the declared secession of seven slave states and the subsequent refusal to recognize their right to secede by the federal government. Historians agree that the incredibly risky choice to secede was due to a push by Southern slaveholders due to fears over the political future of slavery in the United States. In the 11 states that eventually seceded, slaves constituted more than 40 percent of the population and contributed roughly a fourth of the income of whites.

However, in the South less than a quarter of white adult males — the only eligible voters — actually owned slaves. An enduring historical debate, therefore, asks why these Southern non-slave owners would choose to fight and die to preserve slavery?

Most arguments for why non-slaveholders supported secession take three stands. First, even non-slaveholders benefited economically from slavery, and they were heavily invested in preserving the system. Second, they supported secession to preserve white supremacy. Third, they fought to preserve the Southern way of life.

Many scholars have argued that these theories have significant shortcomings and similarly recognize that there was significant Southern opposition to secession. However, these debates lack a careful examination of the various votes held on secession. One contribution of my paper with NYU Abu Dhabi professor Mario Chacón is to use rigorous statistical methods to estimate the relationship between a locality’s dependence on slavery and its electoral support for secession.

We find that an area’s slave dependence heavily predicts support for secession. These findings suggest another puzzle: given that a majority of Southern whites lived in low-slave-dependency areas, how did a democratic process choose to secede over the opposition of the majority?

We answer this question by examining the method by which secession was chosen and the electoral rules that facilitated its success. In each of the six Lower South states that formed the Confederate States of America, the decision to secede was made in specially convened conventions. The delegates to these conventions were elected in special elections and, as we detail below, each convention's decision was not subject to voter ratification. Therefore, the preference of the median delegate to each state’s convention determined that state’s fate.

We first provide significant evidence that a county's dependence on slave labor strongly conditioned its voters' support of pro-secession delegates and then the delegates' support for secession in the various state conventions. We then show that the preference of the median delegate of the convention deviated significantly from that of the state's voters, as the basis of apportionment in the various conventions vastly over-represented the highly slave-dependent regions of each state. In fact, the counties in which a majority of voters supported secession contained less than a third of the states’ voters, yet they elected half of the convention delegates.

We believe this work sheds light on this pivotal episode in U.S. American history. But, a greater contribution is to highlight the importance of institutions such as electoral rules for shaping the outcomes that we observe.

Of course, political scientists realize that “institutions matter." This research shows that even with decisions of enormous consequences, institutions can allow the preferences of a minority to win the day.