Sectionalism grew in southern states due to

several factors, including the reliance on plantation agriculture, the defense of slavery, and a perceived threat to states' rights.

1. Economy: The southern states heavily relied on plantation agriculture, particularly the cultivation of cotton, tobacco, and rice. This agrarian economy shaped the region's social structure and economic system. The profitability of slavery in the plantations created a divide between the North, which was becoming industrialized, and the South, where wealth was concentrated in large slaveholding plantations.

2. Defense of slavery: Slavery was deeply rooted in southern society, and it played a crucial role in fueling sectionalism. Southern planters relied on slave labor to maintain their agricultural dominance, and they defended the institution as a fundamental right. As northern states began to push for abolition, southern states resisted such efforts, further deepening the divide between the two regions.

3. States' rights: Southern states perceived a threat to their autonomy and states' rights as the federal government increasingly sought to limit the expansion of slavery and regulate interstate commerce. The southern states argued for the primacy of states' rights and the idea of nullification, which enabled states to reject federal laws they deemed unconstitutional. This defense of states' rights became a rallying cry for southern sectionalism.

4. Political disagreements: The southern states often found themselves at odds with the growing power of the federal government, particularly on issues such as tariffs and internal improvements. Many southerners believed that these policies favored northern industrial interests at the expense of southern agricultural interests. These political disagreements further fueled sectionalism in the South.

5. Cultural differences: The South developed a distinct regional identity and culture that was characterized by traditions such as honor, chivalry, and an emphasis on agrarian values. This cultural distinctiveness contributed to sectionalism as it created a sense of solidarity and resistance against what was perceived as northern cultural imperialism.

Overall, sectionalism grew in southern states due to the economic, social, political, and cultural factors that shaped the region's development. These factors, particularly the defense of slavery and states' rights, created a deep divide between the North and the South, ultimately leading to the secession of southern states and the outbreak of the American Civil War.