Title: States' rights
Content:  Over following decades, another central dispute over states' rights moved to the forefront. The issue of slavery polarized the union, with the Jeffersonian principles often being used by both sides—anti-slavery Northerners, and Southern slaveholders and secessionists—in debates that ultimately led to the American Civil War. Supporters of slavery often argued that one of the rights of the states was the protection of slave property wherever it went, a position endorsed by the U.S. Supreme Court in 1857 Dred Scott decision. In contrast, opponents of slavery argued that the non-slave-states' rights were violated both by that decision and by the Fugitive Slave Law of 1850. Exactly which—and whose—states' rights were the casus belli in the Civil War remain in controversy.
Title: Origins of the American Civil War
Content:  at the national level as follows: "To the old Union they had said that the Federal power had no authority to interfere with slavery issues in a state. To their new nation they would declare that the state had no power to interfere with a federal protection of slavery. Of all the many testimonials to the fact that slavery, and not states rights, really lay at the heart of their movement, this was the most eloquent of all." W.C. Davis also stated that: "In fact, the state rights defense of secession in 1860–1861 did not really appear in force 
Title: Origins of the American Civil War
Content:  Arthur M. Schlesinger Jr. noted that the states' rights "never had any real vitality independent of underlying conditions of vast social, economic, or political significance." He further elaborated: "From the close of the nullification episode of 1832–1833 to the outbreak of the Civil War, the agitation of state rights was intimately connected with a new issue of growing importance, the slavery question, and the principal form assumed by the doctrine was that of the right of secession. The pro-slavery forces sought refuge in the state rights position as a shield against federal interference with pro-slavery projects. ... As a natural consequence, anti-slavery legislatures in the North were led to lay great stress on the 
Title: Historiographic issues about the American Civil War
Content:  The "States' rights" debate cut across the issues. Southerners argued that under the Tenth Amendment, the federal government's powers limited to those specified in the Constitution, and since it could not take away any state's rights, it therefore had no power to prevent slaves from being carried into new territories. States' rights advocates also cited the Fugitive Slave Clause to demand federal jurisdiction over slaves who escaped into the North. Anti-slavery forces took opposite stances on these issues. The Fugitive Slave Clause in the Constitution was the result of compromises between North and South when the Constitution was written. It was later strengthened by the Fugitive Slave Act that was part of the Compromises of 1850. The Southern politician and states' rights advocate John C. Calhoun regarded the territories as the "common property" of sovereign states, and said that Congress was acting merely as the states' agent.
Title: American Civil War
Content:  Slavery was the main cause of disunion. Slavery had been a controversial issue during the framing of the Constitution but had been left unsettled. The issue of slavery had confounded the nation since its inception, and increasingly separated the United States into a slaveholding South and a free North. The issue was exacerbated by the rapid territorial expansion of the country, which repeatedly brought to the fore the issue of whether new territory should be slaveholding or free. The issue had dominated politics for decades leading up to the war. Key attempts to solve the issue included the Missouri Compromise and the Compromise of 1850, but these only postponed an inevitable showdown over slavery. The motivations of the average 
Title: American Civil War
Content:  A long running dispute over the origin of the Civil War is to what extent states' rights triggered the conflict. The consensus among historians is that the Civil War was not fought about states' rights. But the issue is frequently referenced in popular accounts of the war and has much traction among Southerners. The South argued that just as each state had decided to join the Union, a state had the right to secede—leave the Union—at any time. Northerners (including pro-slavery President Buchanan) rejected that notion as opposed to the will of the Founding Fathers, who said they were setting up a perpetual union. Historian James McPherson points out that even if Confederates genuinely fought over states' rights, it boiled down to states' right to slavery. McPherson writes concerning 
Title: American Civil War
Content:  rights and other non-slavery explanations: "While one or more of these interpretations remain popular among the Sons of Confederate Veterans and other Southern heritage groups, few professional historians now subscribe to them. Of all these interpretations, the states'-rights argument is perhaps the weakest. It fails to ask the question, states' rights for what purpose? States' rights, or sovereignty, was always more a means than an end, an instrument to achieve a certain goal more than a principle." Before the Civil War, the Southern states used federal powers in enforcing and extending slavery at the national level, with the Fugitive Slave Act of 1850 and Dred Scott v. Sandford decision. The faction that pushed for secession often infringed on states' rights. Because of the overrepresentation of pro-slavery factions in 
Title: Origins of the American Civil War
Content:  States' rights was an issue in the 19th century for those who felt that the federal government was superseded by the authority of the individual states and was in violation of the role intended for it by the Founding Fathers of the United States. Kenneth M. Stampp notes that each section used states' rights arguments when convenient, and shifted positions when convenient. For example, the Fugitive Slave Act of 1850 was enacted by southern representatives to use federal authority to suppress northern states' rights. The constitution gave federal protection to slave property rights, and slaveholders demanded that this federal power should be strengthened and take precedence over northern state laws. Anti-slavery forces in northern legislatures had resisted this constitutional right in the form of state personal liberty laws that placed state laws above the federal mandate.
Title: States' rights
Content:  Power, Massachusetts appealed to this protecting principle as often and almost as loudly as South Carolina." Sinha and Richards both argue that the Southerners only advocated states' rights when they disagreed with a policy. Examples given are a states' right to engage in slavery or to suppress freedom of speech. They argue that it was instead the result of the increasing cognitive dissonance in the minds of Northerners and (some) Southern non-slaveowners between the ideals that the United States was founded upon and identified itself as standing for, as expressed in the Declaration of Independence, the Constitution of the United States, and the Bill of Rights, and the reality that the slave-power represented, as what 
Title: Historiographic issues about the American Civil War
Content:  slavery but states' rights. According to Stampp, Stephens became one of the most ardent defenders of the Lost Cause. The historian William C. Davis also mentioned inconsistencies in Southern states' rights arguments. He explained the Confederate Constitution's protection of slavery at the national level as follows:"To the old Union they had said that the Federal power had no authority to interfere with slavery issues in a state. To their new nation they would declare that the state had no power to interfere with a federal protection of slavery. Of all the many testimonials to the fact that slavery, and not states rights, really lay at the heart of their movement, this was the most eloquent of all."

Question: disagreements involving slavery and states' rights were two of the main causes of?
Answer: the American Civil War.