The government plays a huge role in any era, and the 1800s was no exception. Through a series of compromises, rules, crises, and secret deals meant to stifle both sides, tensions increased.
In the 1800s, many people argued that American society was corrupt from top to bottom and needed a complete overhaul, citing slavery and its pervasiveness in all aspects of life (political, economic, and social) as the main reason America was so corrupt. However, there were numerous others who believed that American society was fundamentally sound, and saw slavery as a political problem that needed to be solved.
Beginning in the 1820s, politicians began to try their hand at solving the issue of slavery as a political problem.
In 1820-1821, Congress came up with the Missouri Compromise. In the 1800s, a huge amount of land was purchased by the US government in an event that has come to be known as the Louisiana Purchase. Naturally, Americans wanted to move out to the new territory and begin a new life for themselves...and many wanted to bring their slaves. The purpose of the Missouri Compromise was to address the extension of slavery permanently. There were many people at this time who believed in popular sovereignty, that people should choose whether or not they wanted to enter as a slave state, but that could prove dangerous because the free-slave state balance could be thrown off, skewing the representation in Congress in favor of one of the two sides. The Missouri Compromise resulted in Missouri entering the Union as a slave state and the country being divided in two; all Louisiana Purchase lands north of the 36'30' line would be free states (except for Missouri) and lands south of that line will be slave states.
The US government also decided that they needed to protect American goods and products, so a series of tariffs were levied on the states; these were meant to boost the sales of US products and protect Northern manufacturers. The South exported their cotton to Britain, and received cheap goods in return. In 1816, the government placed a 20-25% tax on all foreign goods; in 1824 that tax rose to 35%; and in 1828 the tax was increased to nearly 50%. The South was furious; no state was selling enough cotton to pay for the goods they needed, and South Carolina deemed the tariff unconstitutional because they believed that the federal government could not pass laws that interfered with state commerce. This Nullification Crisis led to the idea that states' rights superseded the federal law and demonstrated that disputes between various regions of the nation could cause various problems. The Nullification Crisis opened the door to rebellion--if states believed that the federal government's laws did not supersede their own, that meant it would be easier for tensions to rise and for war to eventually break out.
Shortly after the Nullification Crisis, Congress decided to incite the gag rule, tabling all petitions that had to deal with slavery, allowing Congress to effectively ignore them. The gag rule showed that the US was out of step with other countries. By 1836, when the gag rule was put in place, Europe and Britain had already banned slavery. Connected to the gage rule was a series of secret deals, where opposing politicians agreed to keep slavery out of political conversations.
War with Mexico
In the 1840s, the highly divided United States saw itself in a war with Mexico. The Mexican-American War was fought from 1846 to 1848 and was the first war the US armed forces fought on mostly foreign soil.
The Mexican-American War was fought between a militarily weak Mexico against an expansionist United States, led by President James K. Polk who believed that the US had a "manifest destiny" to spread across the North American continent.
Texas gained its independence from Mexico in 1836 but it had not been annexed into the US because they were weary of adding another slave state. Mexico threatened that if Texas was annexed, it would be cause for war. It wasn't until 1844 when James K. Polk had become President, that the US went ahead with the annexation of Texas. Polk also had his eye on the rest of Mexico's territory in North America, and offered to purchase it but was turned down. So, he did what anyone else would do to get what he wanted--he instigated a fight by moving soldiers into a disputed land zone between the Rio Grande and the Nueces River.
On April 25, 1846, Mexican cavalry attacked American soldiers in the disputed zone, killing about a dozen men, and laid siege to an American fort along the Rio Grande.
After months of fighting and losing battles, Mexico turned once again to General Santa Anna, who had been living in exile in Cuba. Santa Anna contacted Polk, saying that if he was allowed to return to Mexico that he would end the war on terms that were favorable to the US. However, Santa Anna double-crossed Polk by taking control of the Mexican army once again and leading it into battle. At the Battle of Buena Vista in February 1847, Santa Anna's army suffered heavy casualties and was forced to withdraw. Meanwhile, US troops landed in Veracruz and captured the city.
On February 2, 1848 the Mexican-American War officially came to an end with the signing of the Treaty of Guadalupe Hidalgo, which would establish the Rio Grande, not the Nueces River, as the US-Mexican border. Mexico also recognized the annexation of Texas and agreed to sell the rest of its North American territory to the US for $15 million.
At the end of the war, Mexico lost about one-third of its territory, and the territory became the states of California, Nevada, Utah, Arizona, and New Mexico.
With the addition of new territory after the Mexican-American War came a lot of issues that needed to be solved in a way to prevent everyone from getting upset (spoiler alert: what's about to happen doesn't necessarily work all that well).
Compromise of 1850
The Compromise of 1850 was a package of five separate bills passed by Congress with the intent to diffuse a four-year confrontation between slave and free states over territory that was acquired during the Mexican-American War.
The Compromise of 1850 consisted of laws that: admitted California as a free state, created Utah and New Mexico territories and allowed them to have popular sovereignty, settled a border dispute between Texas and New Mexico (in Texas's favor), ended the slave trade in Washington, DC., and instilled a new Fugitive Slave Law making it easier for southerners to recover runaway slaves.
The Compromise of 1850 was introduced by Henry Clay, a staunch pro-slavery institutionalist. Clay worked with Daniel Webster of Massachusetts and John C. Calhoun of South Carolina. Webster, although from Massachusetts, backed Clay and antagonized his former abolitionist supporters. Senator Stephen Douglass split the Compromise into five separate bills so Congressmen could vote or abstain on each according to their personal views; all of the individual bills passed and President Millard Fillmore (who was a southern sympathizer and pro-Compromise despite being from New York) signed the bills into law.
The Compromise of 1850 worked as it was intended. It was more or less a patchwork to stave off the impending war, but it did allow both sides to get what they wanted, at least for a time.
These actions, though meant to quell the increasing tensions surrounding slavery, led to the tensions continuing to rise between the abolitionists and the pro-slavery institutionalists, with no end is sight.