Missouri’s admission to the Union in 1821 exposed deep fault lines in American society. But the Compromise created a new sectional consensus that most white Americans, at least, hoped would ensure a lasting peace. Through sustained debates and arguments, white Americans agreed that the Constitution could do little about slavery wherever it already existed and that slavery, with the State of Missouri as the key exception, would never expand north of the 36°30′ line.

Once again westward expansion challenged this consensus, and this time the results proved even more damaging. Tellingly, enslaved southerners were among the first to signal their discontent. A rebellion led by Denmark Vesey in 1822 threatened lives and property throughout the Carolinas. The nation’s religious leaders also expressed a rising discontent with the new status quo. The Second Great Awakening further sharpened political differences by promoting schisms within the major Protestant churches, schisms that also became increasingly sectional in nature. Between 1820 and 1846, sectionalism drew on new political parties, new religious organizations, and new reform movements.

As politics grew more democratic, leaders attacked old inequalities of wealth and power, but in doing so many pandered to a unity under white supremacy. Slavery briefly receded from the nation’s attention in the early 1820s, but that would change quickly. By the last half of the decade, slavery was back, and this time it appeared even more threatening.

Inspired by the social change of Jacksonian democracy, white men regardless of status would gain not only land and jobs, but also the right to vote, the right to serve on juries, the right to attend public schools, and the right to serve in the militia and armed forces. In this post-Missouri context, leaders arose to push the country’s new expansionist desires in aggressive new directions. As they did so, however, the sectional crisis again deepened.

The Democratic Party initially seemed to offer a compelling answer to the problems of sectionalism by promising benefits to white working men of the North, South, and West, while also uniting rural, small town, and urban residents. Indeed, huge numbers of western, southern, and northern workingmen rallied during the 1828 Presidential election behind Andrew Jackson. Slavery’s aristocratic culture was a prickly issue of potential contradiction for the workingman’s party, but Democrats nonetheless had broad appeal in the South, where most men did not own slaves. The Democratic Party tried to avoid the issue of slavery and instead sought to unite Americans around shared racial anxieties and desires to expand the nation.

Democrats were not without their critics during their decade of dominance in the 1830s. In time, the slavery issue again gained energy over ongoing dilemmas about what to do with western lands. Northerners seen as especially friendly to the South had become known as “Doughfaces” during the Missouri debates, and as the 1830s wore on, more and more Doughfaced Democrats became vulnerable to the charge that they served the Southern slave oligarchs better than they served their own northern communities. Whites discontented with the direction of the country used the slur and other critiques to help chip away at Democratic Party majorities. The accusation that northern Democrats were lap-dogs for southern slaveholders had tremendous power.

The major party challenge to the Democrats arose with the Whigs. Whig strongholds often mirrored the patterns of westward migrations out of New England. With an odd coalition of wealthy merchants, middle and upper class farmers, planters in the Upland South, and settlers in the Great Lakes, Whigs struggled to bring a cohesive message to voters during the 1830s. Their strongest support came from places like Ohio’s Western Reserve, the rural and Protestant-dominated areas of Michigan, and similar parts of Protestant and small-town Illinois, particularly the fast-growing towns and cities of the state’s northern half.

Whig leaders stressed Protestant culture, federal-sponsored internal improvements, and courted the support of a variety of reform movements, including of course temperance, Nativism, and even anti-slavery, though few Whigs believed in racial equality. These positions attracted a wide range of figures, including a young convert to politics named Abraham Lincoln. Lincoln admired Whig leader Henry Clay of Kentucky, and by the early 1830s, Lincoln certainly fit the image of developing Whig. A veteran of the Black Hawk War, Lincoln had re-located to New Salem, Illinois, where he worked a variety of odd jobs, living a life of thrift, self-discipline, and sobriety as he educated himself in preparation for a professional life in law and politics.

The Whig Party blamed Democrats for defending slavery at the expense of the American people, but antislavery was never a core component of the Whig platform. Several abolitionists grew so disgusted with the Whigs that they formed their own party, a true antislavery party.  Activists in Warsaw, New York, a small town located outside of Buffalo, went to work and organized the anti-slavery Liberty Party in 1839. Liberty leaders demanded the end of slavery in the District of Columbia, the ending the interstate slave trade, and the prohibition of slavery’s further expansion into the West. But the Liberty Party also shunned women’s participation in the movement, and distanced themselves from visions of true racial egalitarianism. Few Americans voted for the party, however, and the Democrats and Whigs continued to dominate American politics.

Democrats and Whigs fostered a moment of relative calm on the slavery debate, partially aided by gag rules prohibiting discussion of antislavery petitions. Arkansas (1836) and Michigan (1837) became the newest states admitted to the Union, with Arkansas coming in as a slave state, and Michigan coming in as a free state. Michigan gained admission through provisions established in the Northwest Ordinance, while Arkansas came in under the Missouri Compromise. Since its lands were below the line at 36° 30′ the admission of Arkansas did not threaten the Missouri consensus. The balancing act between slavery and freedom continued.

Events in Texas would shatter the balance. Independent Texas soon gained recognition from a supportive Andrew Jackson administration in 1837. But Jackson’s successor, President Martin Van Buren, also a Democrat, soon had reasons to worry about the Republic of Texas. Texas struggled with ongoing conflicts with Mexico and Indian raids from the powerful Comanche. The 1844 democratic presidential candidate James K. Polk sought to bridge the sectional divide by promising new lands to whites north and south. Polk cited the annexation of Texas and the Oregon Territory as campaign cornerstones. Yet as Polk championed the acquisition of these vast new lands, northern Democrats grew annoyed by their southern colleagues, especially when it came to Texas.

For many observers, the debates over Texas statehood illustrated that the federal government had at last moved in a clear pro-slavery direction. Texas President Sam Houston managed to secure a deal with Polk, and gained admission to the Union for Texas in 1845. Anti-slavery northerners were also worried about the admission of Florida, which also entered the Union as slave state in 1845. The year 1845 became a pivotal year in the memory of anti-slavery leaders. As Americans embraced calls to pursue their “Manifest Destiny,” anti-slavery voices looked at developments in Florida and Texas as signs that the sectional crisis had taken an ominous and perhaps irredeemable turn.

The 1840s opened with a number of disturbing developments for anti-slavery leaders. The 1842 Supreme Court case Prigg v. Pennsylvania ruled that the federal government’s Fugitive Slave Act trumped Pennsylvania’s personal liberty law. Antislavery activists believed that the federal government only served southern slaveholders and were trouncing the states’ rights of the North. A number of northern states reacted by passing new personal liberty laws in protest in 1843.

The rising controversy over the status of fugitive slaves swelled partly through the influence of escaped former slaves, including Frederick Douglass. Douglass’s entrance into northern politics marked an important new development in the nation’s coming sectional crisis, as the nation’s beleaguered community of freed black northerners gained perhaps its most powerful voice. Born into slavery in 1818 at Talbot County, Maryland, Douglass grew up, like many enslaved people, barely having known his own mother or date of birth. And yet because of a range of unique privileges afforded him by the circumstances of his upbringing, as well as his own pluck and determination, Douglass managed to learn how to read and write. He used these skills to escape from slavery in 1837, when he was just nineteen. By 1845, Douglass put the finishing touches on his autobiography, Narrative of the Life of Frederick Douglass. The book launched his life-long career as an advocate for the enslaved and the oppressed and helped further raise the visibility of black politics nationally. Other former slaves, including Sojourner Truth joined Douglass in rousing support for antislavery, as did free blacks like Maria Stewart, James McCune Smith, Martin Delaney and numerous others. But black activists did more than deliver speeches. They also attacked fugitive slave laws by helping thousands to escape. The incredible career of Harriet Tubman is one of the more dramatic examples. But the forces of slavery had powerful allies at every level of government.

The year 1846 signaled new reversals to the anti-slavery cause, and the beginnings of a dark new era in American politics. President Polk and his Democratic allies were eager to see western lands brought into the Union, and were especially anxious to see the borders of the nation extended to the shores of the Pacific Ocean. Critics of the administration blasted these efforts as little more than land-grabs on behalf of the slaveholders. Events in early 1846 seemed to justify anti-slavery complaints. Since Mexico had never recognized independent Texas, it continued to lay claim to its lands, even after the United States admitted it to the Union. In January 1846, Polk ordered troops to Texas to enforce claims stemming from its border dispute along the Rio Grande. Polk asked for war on May 11, 1846, and by September 1847, after campaigns conquering all or most of present-day California, New Mexico, Nevada, Utah, Colorado, and Wyoming and Arizona (lands west of the Louisiana Purchase excepting for Pacific Northwest) United States forces entered Mexico City. Whigs, like Abraham Lincoln, found their protests sidelined, but anti-slavery voices were becoming more vocal and more powerful.

After 1846, the sectional crisis raged throughout North America. Debates swirled over whether the new lands would be slave or free. The South began defending slavery as a positive good. At the same time, Congressman David Wilmot submitted his “Wilmot Proviso” late in 1846, banning the expansion of slavery into the territories won from Mexico. The Proviso gained widespread northern support and even passed the House with bipartisan support, but in the Senate it failed.