In 1819 the U. S. had an equal number of slave and free states. Since the beginning of the union, Congress had admitted new states more or less in pairs: one from the North and one from the South. When Missouri applied for admission to the union in 1819 slavery was well established there, and its admission alone as a slave state would thus have upset the delicate balance between North and South. At the same time Maine, formerly the northern part of Massachusetts, applied for admission to the union as a free state. Due in large part to the persuasive skills of Henry Clay of Kentucky, the Speaker of the House of Representatives at the time, Congress eventually adopted in 1820 what became known as the Missouri Compromise which had the following provisions: (1) Missouri admitted to the Union as a slave state; (2) Maine admitted to the Union as a free state; (3) except for Missouri itself, slavery was banned in the territory acquired in the Louisiana Purchase north of the southern boundary of Missouri – the 36°30’ parallel.

Chief Justice Roger Taney and the U. S. Supreme Court in Dred Scott v Sandford in 1857 declared the third provision of the Missouri Compromise unconstitutional because Congress had no power to pass a law which took slave property from their owners in this territory.

By the late 1820s, many citizens of South Carolina had become convinced that the Tariff of 1828 (“the Tariff of Abominations”) was responsible for the depressed state of the South Carolina economy. Some South Carolinians were even considering secession. John C. Calhoun understood that his political future might well depend on how he dealt with this situation. Elected Vice President of the U. S. on a ticket with President Andrew Jackson in 1828, Calhoun anonymously authored the South Carolina Exposition and Protest. The South Carolina Protest was adopted by the state’s legislature in 1828 to announce the state’s intention to nullify the Tariff of 1828. In the Exposition, Calhoun explained and defended the principles upon which the Protest and the argument for nullification rested. Borrowing from Thomas Jefferson and James Madison in the Kentucky and Virginia Resolutions and citing the U. S. Constitution’s Tenth Amendment, he argued that the national government was a creation of the states. Thus, he asserted, the states, not the courts or Congress, were the final judge of the constitutionality of national laws. He suggested that if a state decided Congress had passed an unconstitutional law, for example the Tariff of 1828, the state could declare the law null and void in that state.

James Madison, over eighty years old by this time, denied that nullification was what he argued for in the Virginia Resolution and disavowed Calhoun’s arguments. Calhoun eventually resigned as Vice President in 1832 when the South Carolina legislature chose him to be a new U. S. Senator from South Carolina, and he assumed leadership of those in South Carolina supporting nullification.

For several days in January, 1830 in the U. S. Senate, Senator Robert Hayne of South Carolina and Senator Daniel Webster of Massachusetts engaged in an historic debate about the nature of the union created by the Constitution of the United States. Hayne took the position that the union was a result of a compact between sovereign states. He argued, for example, that “the very life of our system is the independence of the states” and further asserted: “As to the doctrine that the federal government is the exclusive judge of the extent as well as the limitations of its powers, it seems to be utterly subversive of the sovereignty and independence of the states.” Webster argued that the union was a union of the people, not of the states. He asserted that “the union of the states is essential to the prosperity and safety of the states” and that “when the gentleman (Hayne) says the Constitution is a compact between the states, he uses language exactly applicable to the old Confederation. He speaks as if he were in Congress before 1789.” Hayne’s view was known as the doctrine of state sovereignty, and Webster’s view was known as unionism. Whereas Hayne believed that the states were the final judges of the constitutionality of national laws, Webster believed that role was properly filled by the U. S. Supreme Court.

Hayne attempted to use the Virginia and Kentucky Resolutions of 1798 to support his view. John C. Calhoun was Vice President of the United States, and thus President of the Senate, during the Hayne-Webster debate and supported Hayne’s view. Webster’s unionist view was supported by fellow U. S. Senator Henry Clay of Kentucky as well as by former President John Quincy Adams and President Andrew Jackson.

In 1849 President Zachary Taylor decided to support statehood for California and New Mexico, knowing that they would be admitted as free states. Southerners were upset and talk of secession grew. Various bills to address this issue were introduced in the U. S. Congress in January, 1850. One of these was a compromise plan put forth by Kentuckian Henry Clay who, at the age of 73, was back in the U. S. Senate. Clay visited with Senator Daniel Webster of Massachusetts and secured Webster’s approval for his proposed compromise. Clay introduced eight resolutions each of which offered concessions to either northerners or southerners. Senator John C. Calhoun of South Carolina opposed Clay’s plan but died three weeks after a speech opposing it. President Taylor died in July,1850. The new President, Millard Fillmore, was a friend and ally of Daniel Webster and a strong supporter of Clay’s plan. After Webster resigned his Senate seat to become Fillmore’s Secretary of State, Senator Stephen Douglas of Illinois led the drive to get Clay’s compromise plan adopted. Finally, by the latter part of 1850, five separate parts of the Compromise of 1850 were adopted: (1) California admitted to the union as a free state; (2) territorial governments and boundaries for Utah and New Mexico established, and their status as free or slave states to be determined by popular sovereignty; (3) the slave trade in the District of Columbia abolished by 1851; (4) the 1793 Fugitive Slave Act amended by removing cases from a state’s jurisdiction and appointing federal commissioners to conduct hearings and issue arrest warrants, and slaves prohibited from having jury trials or testifying on their own behalf; and (5) the Texas-New Mexico boundary established, and Texas paid $10 million for the loss of New Mexico land.

The Fugitive Slave Act may have been the most controversial part of the Compromise of 1850. Henry Clay included it to satisfy southerners upset by other parts of the Compromise. There had been a Fugitive Slave law since 1793 based on Article IV, Section 2, Clause 3 of the U. S. Constitution. For that reason, fugitive slaves found it safer to flee to Canada where slavery was forbidden. As more in the North turned against slavery, free states gave slave owners less and less cooperation in apprehending their escaped slaves. The 1850 Fugitive Slave Act was an attempt to remedy Southern slave owners’ problems with the 1793 law. The 1850 act set up a federal enforcement operation which consisted of U. S. commissioners with the power to issue warrants for fugitive slaves and to make judgment in fugitive cases without a hearing solely on the basis of an affidavit of ownership by the slave owner. The commissioners received a $10 fee for each slave returned to slavery and only $5 otherwise. The act did not set up a statute of limitations for runaway slaves which meant that runaways from years ago, could be captured and returned to slavery. The act also threatened local law enforcement officers and citizens with fines of up to $1,000 and liability for civil suits if they harbored fugitive slaves or refused to cooperate with recapture efforts.

Northerners who had never been seriously anti-slavery now witnessed public capture and extradition of runaway slaves that revealed slavery in all its cruelty. This served to add to Northern opposition to slavery. The Act also resulted in the growth of the Underground Railroad, a network of people providing shelter and other assistance for escaped slaves traveling north.

Senator Stephen Douglas of Illinois, a Democrat, introduced the legislation which became the Kansas-Nebraska Act in January, 1854. His intent was to open land west of the Mississippi to further settlement as well as to lay the groundwork for a transcontinental railroad from Chicago to the Pacific Coast. Debate over the Act quickly shifted to a bitter fight over the expansion of slavery into the remaining unorganized territory of the Louisiana Purchase. Douglas realized that he needed the support of southerners to pass the Act, and some southern senators insisted that slavery must be permitted in the territory. He achieved some southern support by the adoption of the idea of “popular sovereignty” which meant that the people who settled the land would determine for themselves whether the area would be slave or free. This conflicted with the Missouri Compromise of 1820 which provided that, except for Missouri, the rest of the Louisiana Purchase territory above 36 30 would be free of slavery. With the passage of the Kansas-Nebraska Act, this provision of the 1820 Missouri Compromise was thus inoperative and void. According to the Kansas-Nebraska Act, its intent was neither to legislate slavery for any territory or state nor to exclude it. Instead, the Act left the people in each territory free to decide the slavery issue as they saw fit.

Less than two days after congressional adoption of the Kansas-Nebraska Act, violence broke out in Kansas leading to bloodshed in what became called “Bleeding Kansas.” Threats of secession were again heard in some states. There were numerous political consequences: the Democratic Party suffered in the North; the Whig Party fell apart; the Know-Nothing movement surged for a while; and the new Republican Party emerged at Ripon, Wisconsin. Dismayed by the Kansas-Nebraska Act, Abraham Lincoln, a former one-term Congressman from Illinois, re-entered politics to lead this new Republican Party in Illinois and engaged in a series of historic debates with Senator Douglas. One of the nation’s most recognized scholars on the Civil War, Professor James McPherson, in his Battle Cry of Freedom: The Civil War Era, writes: “The Kansas-Nebraska Act may have been the most important single event pushing the nation toward civil war.”

Abraham Lincoln delivered his Cooper Union Address on February 27, 1860 in New York City at the Cooper Institute in Manhattan. The Young Men’s Republican Union sponsored the speech. Among the members of the Union’s board were Horace Greeley and William Cullen Bryant both of whom opposed William Seward’s becoming the Republican Party’s nominee for President in 1860. At the time, Lincoln was an unannounced candidate for the party’s presidential nomination and hoped that by this speech he might gain support for his nomination.

Lincoln defended the Republican Party’s view that Congress had the power under the U. S. Constitution to control slavery in new territory. He asserted that the party’s view on this issue was identical to that of a majority of the men who signed the new Constitution. He referred to the Northwest Ordinance’s prohibition of slavery in new territory adopted in 1787 and reauthorized by the First Congress in 1789 as further proof that Congress was understood to have the power to ban slavery.

Lincoln stated the Republican Party’s position should not alarm Southerners because he acknowledged that the national government did not have the power to free the slaves in the states where is already existed. But he urged his fellow Republicans not to surrender to Southern demands to recognize slavery as being right. He concluded: “Let us have faith that right makes might, and in that faith, let us, to the end, dare to do our duty as we understand it.”

Lincoln’s speech excited his listeners and gained him political support for the Republican presidential nomination in New York, Seward’s home territory.

The question whether slavery should be allowed in territories acquired by the U.S. was a controversial one prior to the Civil War. Dred Scott, a slave, was taken by his master from Missouri (a slave state) first to Illinois (a free state) and then to Wisconsin Territory where slavery under the Missouri Compromise of 1820 was forbidden. Later, with his owner, Dred Scott returned to Missouri. Dred Scott and his wife filed a petition in a Missouri court requesting permission to file suit in order to establish their right to be freed since they had resided on free soil. After two trials and the Scotts temporarily winning their freedom, the Missouri Supreme Court reversed the lower court’s judgment and held that the Scotts’ residence on free soil had not changed their status as slaves. The Scotts then brought suit in a U. S. Circuit Court where the verdict once more was that they were still slaves. The case was then appealed to the U. S. Supreme Court.

Seven of the nine Supreme Court Justices concluded that the Scotts remained slaves. Chief Justice Roger Taney authored the most important opinion for a majority of the Court. Taney first addressed the question of whether the Scotts were citizens and thus entitled to bring suit in a U. S. court. He wrote: “We think they are not, and that they are not included, and were not intended to be included, under the word ‘citizens’ in the Constitution and can, therefore, claim none of the rights and privileges which that instrument provides for and secures to citizens of the United States.” Still writing for a majority of the Court, Taney also wrote: “…it is the opinion of the Court that the Act of Congress (the Missouri Compromise of 1820) which prohibited a citizen from holding and owning property of this kind in the territory of the United States north of the line therein mentioned, is not warranted by the Constitution, and is therefore void.” The Court thus declared the Missouri Compromise unconstitutional and in the process emphasized the importance of protecting property rights, in this case property being slaves.

The first sentence of Section 1 of the Fourteenth Amendment added to the Constitution in 1868 declares that “all persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside.” It was written and added to the Constitution for the specific purpose of overruling the Supreme Court’s decision in Dred Scott v Sanford.