It marked a turning point in the ongoing debate over slavery and its expansion into new territories. At the heart of the crisis was whether Missouri, part of the Louisiana Purchase, would be admitted to the Union as a free or slave state. A fire bell in the night is seen as something that wakes you with terror; Thomas Jefferson referred to the Missouri Crisis as a “fire bell in the night.” He was referring to his fear of the westward expansion of slavery. This fear was proper to have; just forty years later, America would enter a war between the Northern and Southern states over