In Gary J. Kornblith’s article, “Rethinking the Coming of the Civil War: A Counterfactual Exercise,” Kornblith argues against fundamentalist historians who claim that the major economic, social and political differences between the North and the South made the Civil War inevitable. He posits that had Henry Clay defeated James K. Polk in the presidential election of 1844 (an election that was determined by a few thousand votes in New York), the Mexican-American War would not have occurred and thus the sectional debate about whether or not to expand slavery into territories gained by the war would not have occurred. Ultimately this would have prevented hostilities over slavery from becoming intense enough to lead to the development of the Republican Party, Lincoln’s election and then Southern secession. Although it takes a substantial amount of explaining for Kornblith to make his counterfactual situation clear, his ultimate argument is that the Civil War was not, as fundamentalists argue, inevitable (at least at the time that it occurred), but rather it was caused by the Mexican-American war and the conflicts that arose from territorial gains (102).
Kornblith argues that “partisan identities counterbalanced sectional identities” during the late 1840s, and as such, the political crises of the 1850s that resulted in the formation of the Republican Party need not have happened (89). That is, he argues that without a major political crisis, the sectional differences between the North and the South were not a major threat to national unity because within the North and South major political differences existed. However, there ultimately was a crisis in the Second Party System that resulted in major political changes, and Kornblith notes that “the conflicting passions aroused by the [Wilmot] Proviso most definitely proved a threat to the national parties and to the nation itself,” (89). Thus Kornblith blames the controversy over the Wilmot Proviso, a failed piece of legislation that would have banned slavery in territories gained during the Mexican-American War, for the tensions in the US political system that led to the breakdown of the Second Party System.
Additionally, Kornblith argues that without the conflict over the Wilmot Proviso, the Fugitive Slave Law passed in the early 1850s would have been less harsh because “absent other evidence of southern aggression, most northern whites would probably have accepted a moderately strengthened fugitive slave law,” (96). Because the South became particularly jealous of the future of slavery during conflicts over the expansion of slavery, Northerners became concerned over the passion with which Southerners defended slavery and became antagonistic towards slavery and the South.
Kornblith concludes his argument and his “counterfactual thought experiment,” stating, “we can conclude that the Mexican-American was a necessary, if not sufficient, cause of the Civil War” (102). I would tend to agree with him. Ultimately, the political and social crises of the 1850s had their roots in the territories gained during the Mexican-American War. However, Kornblith goes farther and argues that absent the Civil War, “the South’s peculiar institution would almost surely have persisted beyond 1900” (102). This seems to me to be too much of a stretch; he notes that the Wilmot Proviso was the first time that issues of popular sovereignty came into the debate about slavery, and that the Compromise of 1850, which resulted from the Proviso, led to a northern belief in a southern “slave power conspiracy,” (99). Although that may be the case, it is flawed to then believe that these issues would not have occurred under other circumstances. The Mexican-American war led to a substantial increase in US territory, but any slight alteration to the fragile truce the North and the South held over the issue of slavery could have easily resulted in major conflicts that could have led to war or abolition. In that sense, Kornblith’s counterfactual scenario can help us to understand the specific events leading up to the Civil War, but to then make hypotheses about what might have happened instead of the war is to go too far.