Everyone agrees that there was a sequence of major events from 1850 to 1861 that led to the out break of the civil war. It can also be referred to as the break up of the union. One might notice that these factors have one common trait: the conflict over slavery. But the four that convey this message the most strongly are the conflict over states of territories, the compromise of 1850, agitation over slavery, and lastly the national parties in crisis and the Kansas-Nebraska Act of 1854. Southerners met the Wilmot Proviso with hostility and that they in turn developed the Compromise of 1850. This would quell tempers as well as thoughts of secession until the Kansas-Nebraska Act was passed and changed the course of history. First of all, the conflicts over both states and territories were gaining momentum. Even though these conflicts had been going on for a while, it was because of their juxtaposition with the other factors that they managed to accomplish what they did.
The issue of slavery in the territories really brought in the Mexican War because of its sectional focus in the late 1840’s. There was the Wilmot Proviso. The Wilmot Proviso excluded slavery from the new territories. Southerners met the Wilmot Proviso with hostility. This would have upset the Compromise of 1820 and the balance of the fifteen free states and the fifteen slave states. The defeat of the war only intensified sectional feelings. On the issue of how to deal with these new western territories, there were essentially three conflicting positions. The Southern position viewed any attempt at restricting the expansion of slavery as a violation of their constitutional right to take and use their property as they pleased. Lewis Cass was a Senator from Michigan and he came up with a compromise that won a considerable amount of approval from both the south and north. He proposed that instead of Congress determining whether to allow slavery in a new western state, that the matter should be.