To understand about Bleeding Kansas, you need to know about the Kansas-Nebraska Act of 1854, and to understand that, you have to see the connection between the results of the Mexican War, on the one hand, and the Missouri Compromise, on the other. This is why history is usually related past-forward-to-future, rather than future-back-to-past!
First, we must jump way back to 1820 and the Missouri Compromise. We’ll look at it in a little more detail later, but for now it is enough to remember that it did two things: It established the precedent of admitting one free state and one slave state simultaneously, so that the South, already outnumbered in the House of Representatives, would not find itself also outnumbered in the Senate. It also established a latitude (parallel 36°30′ north), above which slavery would be forever forbidden, except in the newly admitted state of Missouri.
Both provisions kept the Union together for a crucial thirty years. The first was abandoned in 1850, when California was admitted as a free state (see below). Four years later, the Kansas-Nebraska Act (again, see below) abandoned the second principle: Henceforth territories would be admitted as free states or slave states not depending on whether they were above or below the compromise line, but according to the wishes of each territory’s inhabitants at the time of admission. This “popular sovereignty” idea may have seemed sensible and democratic. In practice, it was disastrous.
Of the two territories being considered for admission to the Union, Nebraska was universally recognized as lying too far north for slavery. All the more reason, according to certain Southern hot-heads, why Kansas must be admitted as a slave state. California had already upset the balance. To add two more free states, rather than one free and one slave, would worsen the South’s already outnumbered position. More immediately, pro-slavery men in neighboring Missouri, already bordered by the free states of Illinois and Iowa, were alarmed at the idea of yet another free state to the west. They determined to avoid this by hook or by crook, especially crook.
Slavery advocates organized immigration to Kansas Territory from slave states, and established pro-slavery settlements near the Missouri border, at Leavenworth and Atchison. Then anti-slavery organizations in the North organized and funded Free-State immigration, traveling through Iowa and Nebraska when Missouri proved hostile, establishing Free-State settlements farther west in Topeka, Manhattan, and Lawrence, and pretty quickly establishing an anti-slavery majority in the state. But in November, 1854, thousands of armed pro-slavery men from Missouri (“Border Ruffians“) entered the state, posed as residents, and voted in the election to Congress of the territorial delegate allotted to Kansas. Given this rather extra-legal assistance (6,000 men voted, out of a total of 1,500 registered voters, not all of whom voted) pro-slavery forces won the election. The following March, the Border Ruffians did it again, packing the ballot boxes in favor of pro-slavery delegates to the first territorial legislature.
But by the summer of 1855, approximately 1,200 New Englanders had traveled to Kansas, armed and ready to resist coercion in or from Missouri. When the pro-slavery territorial legislature began to pass laws to institutionalize slavery in Kansas Territory, Free-Soilers drafted their own constitution and formed their own government. The stage was set for a pocket-sized preview of the Civil War. In October 1855, John Brown and some of his sons came to Kansas Territory.
In November and December, 1855, the first violent clashes occurred. In January, 1856, in Washington, D.C., President Franklin Pierce declared the Free-State Topeka government to be illegitimate! In May, Border Ruffians attacked Lawrence, burned the Free State Hotel, destroyed two newspaper offices and their printing presses, and ransacked homes and stores. Now events began to run out of hand, sped by telegraphed accounts of events hundreds of miles from each other.
The day after the Border Ruffian raid on Lawrence, South Carolina Representative Preston Brooks attacked Massachusetts Free Soil Senator Charles Sumner in the Senate chambers with his thick cane. He hit him and continued to hit him until he was unconscious, while another gallant Southern representative, holding a pistol, refused to let anyone help Sumner. (It was another three years before Sumner was able to return to his Senate duties.)
Physical violence on the Senate floor! In response, John Brown led an attack on a pro-slavery settlement at Pottawatomie Creek which dragged five pro-slavery men from their homes and hacked them to death with broadswords. On June 2, at the Battle of Black Jack, he took two dozen pro-slavery soldiers prisoner. On July 4, the president sent federal troops to prevent the shadow government in Topeka from meeting. In August, thousands of proslavery men formed into armies and marched into Kansas. Hostilities continued until Brown departed and a new territorial governor, John W. Geary, managed to secure a fragile peace.
In 1857, a Kansas constitutional convention drafted the pro-slavery “Lecompton Constitution,” and it was ratified when anti-slavery forces boycotted an election that offered no way to vote against slavery. President James Buchanan accepted the vote, but Congress disagreed and ordered another election. In the second election the pro-slavery forces boycotted the process, the anti-slavery forces won, and the Lecompton Constitution was dead. Violence flickered on and off until, by 1859, the death toll had reached 56. In mid-year, residents voted 2-to-1 for the anti-slavery Wyandotte Constitution. A year and a half later, on January 29, 1861, Kansas entered the Union as a free state. By that time, South Carolina had already declared itself out of the union, and other slave states (though not all of them) were on their way. Bleeding Kansas had done its bit to bring on a war that would kill or wound more than 10,000 men for every one of the 56 who died on that frontier.