In national politics, sectionalism is loyalty to the interests of one's own region or section of the country, rather than to the country as a whole. It is often a precursor to separatism.
Sectionalism occurs in the United Kingdom, most notably in the constituent country of Scotland, where various sectionalist/separatist political organisations and parties have existed since the early 1920s, beginning with the Scots National League. Today, Scottish sectionalism is most strongly associated and advocated by the Scottish National Party(SNP), which can be described as both sectionalist and separatist. The SNP advocates for both Scottish independence and more autonomy for Scotland while remaining a part of the United Kingdom.
Sectionalism in 1800s America refers to the different lifestyles, social structures, customs, and political values of the North and the South. It increased steadily in 1800–1850 as the North industrialized, urbanized and built prosperous factories, while the deep South concentrated on plantation agriculture based on slave labor, together with subsistence farming for poor whites who owned no slaves. Southerners defended slavery in part by claiming that Northern factory workers toiled under worse conditions and were not cared for by their employers. Defenders of slavery referred to factory workers as the "white slaves of the North".
Meanwhile, Northern industrialists and workers benefited from the slave system, even as Northern politicians and religious leaders denounced it. The South expanded into rich new lands in the Southwest (from Alabama to Texas). However, slavery declined in the border states and could barely survive in cities and industrial areas (it was fading out in cities such as Baltimore, Louisville and St. Louis), so a South based on slavery was rural and non-industrial. On the other hand, as the demand for cotton grew the price of slaves soared, as slaves were considered imperative for the harvest and refinement of cotton. Historians have debated whether economic differences between the industrial Northeast and the agricultural South helped cause the Civil War. Most historians now disagree with the economic determinism of historian Charles Beard in the 1920s and emphasize that Northern and Southern economies were largely complementary.
Historians do agree that social and cultural institutions were very different in the North and South. In the South, wealthy men owned all of the quality land, leaving poor white farmers with marginal lands of low productivity. Fears of slave revolts and abolitionist propaganda made the South militantly hostile to suspicious ideas. Members and politicians of the newly formed Republican Party were extremely critical of Southern society and argued that the system of free labor in place in the North resulted in much more prosperity. Republicans criticizing the Southern system of slavery would commonly cite the larger population growth of the Northern states, alongside their rapid growth in factories, farms, and schools as evidence of the superiority of a free labor system.
Southerners argued that it was the North that was changing, and was prone to new "isms", while the South remained true to the historic republican values of the Founding Fathers (many of whom owned slaves, including Washington, Jefferson and Madison.) The issue of accepting slavery (in the guise of rejecting slave-owning bishops and missionaries) split the largest religious denominations (the Methodist, Baptist and Presbyterian churches) into separate Northern and Southern denominations. Industrialization meant that seven out of eight European immigrants settled in the North. The movement of twice as many whites leaving the South for the North contributed to the South's defensive-aggressive political behavior.
Sectionalism has also existed in the American West. Farmers in the late 19th century, feeling exploited by railroads headquartered in the East, supported the Populist political movement.
Sectionalism can be found in the Spanish regions of Catalonia, the Spanish portion of the Basque Country, Galicia, and Andalusia.