Sean Wilentz: Responds to criticism his book is a brief for Democrats
Siegel raises an interesting historical point. The Whig Party, he argues, was"the center of opposition to both slavery and the Mexican War," while the Jacksonians were a party"of strong slaveholding interests." But this is simplified and misleading. Until the 1850s, the Whigs included most of the wealthiest southern slaveholders and some of the nation's most outspoken pro-slavery ideologues (many of whom also opposed the Mexican War, as did the fractious John C. Calhoun, for pro-slavery reasons). Pro-war but anti-slavery northern Democrats led the fight to keep slavery out of all territories acquired from Mexico. Thereafter, the bulk of the support for the antislavery Free Soil Party in 1848 came from alienated Democrats.
My book argues, in some detail, that the national mainstream of both parties were dedicated to keeping the slavery issue out of national politics. This proved impossible in the 1850s, leading to the Whigs' demise and, by 1860, to the Democrats' division into two sectional political parties. Easier versions of history, pitting Whig"good guys" against Jacksonian"bad guys" on slavery, caricature the historical evidence.