William J. Cooper Jr. set out at first to write a history of the Democratic Party in the antebellum South. Yet his reading of antebellum newspapers and manuscripts of southern politicians persuaded him that slavery dominated the region's political concerns decades before the sectional strife of the 1850s that led to civil war. In The South and the Politics of Slavery, Cooper argues that throughout the era of the second party system (Democrats vs. Whigs), both southern Democrats and southern Whigs competed to portray their particular party as the best defender of slavery. The specific issues varied over time, from denouncing abolitionism to demanding the expansion of slavery into the former Mexican territories. But the controlling theme of southern politics, according to Cooper, remained essentially the same from Jackson's presidency to Buchanan's.

While politics in the North was locally oriented, southern politics was usually slavery oriented. Local issues paled in significance next to slavery, the defense of which represented "independence, honor, and equality" to white southern voters, whether they owned slaves or not. For the non-slaveholding majority, African chattel slavery supported the dignity of all white men, keeping even poor whites out of a condition of servitude and implying a rough equality among men of the "master race."

Cooper does not allege that southern politicians chose their careers in order to defend slavery. Like their northern counterparts, southern politicians sought power, recognition, influence, and related forms of success. But in order to maintain political success in a South with a growing electorate, politicians had to consistently conform to the unwritten rules of the politics of slavery.

Each party contended for the role of slavery's white knight, while blaming the opposing party for ties to abolitionist northerners. At the same time, both Democrats and Whigs in the South proffered the national party structure as the best means to defend slavery by containing northern opposition. The powerful John C. Calhoun of South Carolina and his followers throughout the South rejected this reasoning. Calhounites sought to factionalize politics along sectional lines alone, thus coming to occupy a shifting position at the fulcrum between southern Democrats and southern Whigs.

In the early years of the second party system, southern politicians succeeded in gaining the acquiescence of their northern partners on slavery issues, as well as in selecting presidential candidates who, if not slaveholders themselves, could be expected to cooperate reliably with the South's agenda. By the 1850s, however, under pressure from increasing northern resistance to southern demands, only the Democrats were able to maintain even a pretense of unity as the party system collapsed. The Whigs, along with the upstart Know-Nothings, disintegrated by 1856, and the Democrats were riven by sectional factions.

Cooper's book, while valuable and provocative, downplays the element of contingency and seems to imply that slavery was somehow destined to dominate southern politics. For instance, Cooper labels the southern Whigs' political romance with Henry Clay and economic nationalism as "the great aberration," but this is a ploy that dismisses the phenomenon without explaining it. Had the Whig administration of William Henry Harrison lasted for more than a month, the southern Whigs' conversion to economic issues besides slavery might have been longer lasting. Similarly, if Harrison's successor, John Tyler, had not so aggressively pursued the annexation of Texas, a slave state, then neither the sectionalism in Congress nor the mood of desperation among southern politicians need have been as drastic as they became.

Cooper's selection of sources, especially his decision to confine his research to the eleven future Confederate states, may have also tended to downplay other issues that mattered in the politics of slave states, including those that did not secede. Finally, by lumping Democrats and Whigs together as exemplars of the "politics of slavery" in action, Cooper minimizes the perceived differences between the parties, the attractions of patronage, and the value assigned to party loyalty, often across generations.

Despite these criticisms, the book certainly does shed light on a genuine and crucial fact of southern political life. This book provides evidence to back the assessment of a shrewd 19th-century observer, John Quincy Adams, the former president who went on to serve in the House of Representatives with southern colleagues. In 1835 Adams described the "paramount" position of slavery in southern political concerns. Southern politicians, he noted, "never failed to touch upon this key ... and it has never yet failed of success."